1
Brake Drums  -  Drive (4)
                                      140
                                      11
Brake Drums  -  Non Drive (2)
                                      60
                                       8
Frame Rails
                                      440
                                      87
Crossmember - Cab
                                      15
                                       5
Crossmember  -  Suspension
                                      25
                                       6
Crossmember  -  Non Suspension (3)
                                      15
                                       5
Fifth Wheel
                                      100
                                      25
Radiator Support
                                      20
                                       6
Fan Shroud
                                      10
                                       2
Fuel Tank Support Structure
                                      40
                                      12
Steps
                                      35
                                       6
Bumper
                                      33
                                      10
Shackles
                                      10
                                       3
Front Axle
                                      60
                                      15
Suspension Brackets, Hangers
                                      100
                                      30
Transmission Case
                                      50
                                      12
Clutch Housing
                                      40
                                      10
Drive Axle Hubs (8)
                                      160
                                       4
Non Drive Front Hubs (2)
                                      40
                                       5
Driveshaft
                                      20
                                       5
Transmission/Clutch Shift Levers
                                      20
                                       4

EPA and NHTSA are specifying the baseline vehicle weight for each regulatory vehicle subcategory (including the tires, wheels, frame, and cab components) in GEM in aggregate based on weight of vehicles used in EPA's aerodynamic test program, but allow manufacturers to specify the use of light-weight components.  GEM then quantifies the weight reductions based on the pre-determined weight of the baseline component minus the pre-determined weight of the component made from light-weight material.  Manufacturers cannot specify the weight of the light-weight component themselves, only the material used in the substitute component.  The agencies assume the baseline wheel and tire configuration contains dual tires with steel wheels, along with steel frame and cab components, because these represent the vast majority of new vehicle configurations today.  The weight reduction due to replacement of components with light weight versions will be reflected partially in the payload tons and partially in reducing the overall weight of the vehicle run in GEM.  The specified payload in GEM will be set to the prescribed payload plus one third of the weight reduction amount to recognize that approximately one third of the truck miles are travelled at maximum payload, as discussed below in the payload discussion.  The other two thirds of the weight reduction will be subtracted from the overall vehicle weight prescribed in GEM.
 In the context of this heavy-duty vehicle program with only changes to tires and wheels, the agencies do not foresee any related impact on safety.
Extended Idle Reduction Technology Assessment
Extended idling from Class 8 heavy-duty long haul combination tractors contributes to significant CO2 emissions and fuel consumption in the United States.  The Federal Motor Carrier Safety Administration regulations require a certain amount of driver rest for a corresponding period of driving hours.  Extended idle occurs when Class 8 long haul drivers rest in the sleeper cab compartment during rest periods as drivers find it both convenient and less expensive to rest in the truck cab itself than to pull off the road and find accommodations. During this rest period a driver will idle the truck in order to provide heating or cooling, or to run on-board appliances.  In some cases the engine can idle in excess of 10 hours.  During this period, the truck will consume approximately 0.8 gallons of fuel and emit over 8,000 grams of CO2 per hour. An average truck can consume 8 gallons of fuel and emit over 80,000 grams of CO2 during overnight idling in such a case.
Idling reduction technologies (IRT) are available to allow for driver comfort while reducing fuel consumptions and CO2 emissions. Auxiliary power units, fuel operated heaters, battery supplied air conditioning, and thermal storage systems are among the technologies available today.  The agencies are adopting a provision for use of extended idle reduction technology as an input to the GEM for Class 8 sleeper cabs.  As discussed further in Section III, if a manufacturer wishes to receive credit for using IRT to meet the standard, then an automatic main engine shutoff must be programmed and enabled, such that engine shutdown occurs after 5 minutes of idling, to help ensure the reductions are realized in-use.  A discussion of the provisions the agencies are adopting for allowing an override of this automatic shutdown can be found in RIA Chapter 2.  As with all of the technology inputs discussed in this section, the agencies are not mandating the use of idle reductions or idle shutdown, but rather allowing their use as one part of a suite of technologies feasible for reducing fuel consumption and meeting the final standards and using these technologies as the inputs to the GEM.  The default value (5 g CO2/ton-mile or 0.5 gal/1,000 ton-mile) for the use of automatic engine shutdown (AES) with idle reduction technologies was determined as the difference between a baseline main engine with idle fuel consumption of 0.8 gallons per hour that idles 1,800 hours and travels 125,000 miles per year, and a diesel auxiliary power unit operating in lieu of main engine during those same idling hours.  The agencies received comments regarding the assumptions used to derive the idle reduction value.  The agencies are finalizing the calculation as proposed.  Additional details regarding the comments and calculations are included in RIA Section <IP_ADDRESS>.
The agencies are adopting a provision to allow manufacturers to provide an AES system which is active for only a portion of a vehicle's life.  In this case, a discounted idle reduction value would be entered into GEM.  A discussion of the calculation of a discounted IRT credit can be found in Section III.  Additional details on the emission and fuel consumption reduction values are included in RIA Section <IP_ADDRESS>.
Vehicle Speed Limiters
The NPRM proposed to allow combination tractors that use vehicle speed limiters (VSL) to include the maximum governed speed value as an input to the GEM model for purposes of determining compliance with the vehicle standards. See 75 FR at 74223. Governing the top speed of a vehicle can reduce fuel consumption and GHG emissions, because fuel consumption and CO2 emissions increase proportionally to the cube of vehicle speed.  Limiting the speed of a vehicle reduces the fuel consumed, which in turn reduces the amount of CO2 emitted.  The specific input to the GEM model would be the maximum governed speed limit of the VSL that is programmed into the powertrain control module (PCM).  The agencies stressed in the NPRM that in order to obtain a benefit in the GEM model, a manufacturer must preset the limiter in such a way that the setting will not be "capable of being easily overridden by the fleet or the owner."  If the top speed could be easily overridden, the fuel consumption/CO2 benefits of the VSL might not be realized, and the agencies did not want to allow the technology to be used for compliance if the technology could be disabled easily and the real world benefits not achieved.
Many commenters (Cummins, Daimler, EMA/TMA, ATA, AAPC, NADA) supported the use of VSLs as an input to the GEM model, but requested clarification of what the specific requirements would be to ensure the VSL setting would not be capable of being easily overridden.  Cummins and Daimler requested that the final rules explicitly allow vehicle manufacturers to access and adjust the VSL control feature for setting the maximum governed speed, arguing that the diverse needs of the commercial vehicle industry warrant flexibility in electronic control features, and that otherwise supply chain issues may result from the use of VSLs.  NADA and EMA/TMA also requested that VSLs have override features and be adjustable, citing various needs for flexibility by the fleets.  EMA/TMA and ATA requested that VSLs be adjustable downward by fleets in order to obtain greater benefit in GEM, if company policies change or if a subsequent vehicle owner needs a different VSL setting.  EMA/TMA stated that the agencies should prohibit tampering with VSLs, and both EMA and TRALA requested more information on how the agencies intended to address tampering with VSLs.
In addition to features governing the maximum vehicle speed, commenters requested adding other programmable flexibilities to mitigate potential drawbacks to VSLs.  Cummins, DTNA, and EMA/TMA requested that a programmable "soft top" speed be added to PCMs which would allow a vehicle to exceed the speed limit setting governed by a VSL for a short period of time.  A "soft top" feature could be used for a limited duration in order to maneuver and pass other on-road vehicles at speeds greater than that governed by the VSL. The commenters argued this was important for vehicle passing and safety-related situations where, without a soft top feature, it could be possible for speed limited trucks to obstruct other vehicles on the road and cause severe road congestion.
ATA and EMA/TMA also requested that manufacturers be allowed to program a mileage based expiration into the VSL control feature, in order to preserve the value of vehicles for second owners who may require operation at higher speeds.  ATA further commented that manufacturers should be allowed to account for additional GEM input benefits if the speed governor is reprogrammed to a lower speed within the useful life of the vehicle.
After carefully considering the comments, the agencies have decided, for these final rules, to retain most of the elements in the proposal.  Manufacturers will be allowed to implement a fixed maximum governed vehicle speed through a VSL feature and to use the maximum governed vehicle speed as an input to the GEM for certification.
The agencies have decided to adopt commenters' suggestions to allow adjustable lower limits that can be set and governed by VSLs independent of the one governing the maximum certified speed limit to provide the desired flexibility requested by the trucking industry.  We believe that this flexibility would not decrease the anticipated fuel consumption/CO2 benefits of VSLs because the adjustable limits would be lower values.  Issues identified by the commenters including the ability to change delivery routes requiring lower governed speeds or when a fleet's business practices change resulting in a desire for greater fuel consumption savings are not in conflict with the purpose and benefit of VSLs.  As such, the agencies have decided to allow a manufacturer to install features for its fleet customers to set their own lower adjustable limits below the maximum VSL limit specified by the agencies.  However, the agencies have decided to not allow any additional benefit in GEM to a manufacturer for allowing a lower governed speed in-use than the certified maximum limit for this first phase of the HD National Program because we can only be certain that the VSL will be at the maximum setting.
Both agencies also agree that manufacturers can provide a "soft top" and expiration features to be programmed into PCMs to provide additional flexibility for fleet owners and so that fleets who purchase used vehicles have the ability to have different VSL policies than the original owner of the vehicle.  Although the agencies considered limiting the soft top maximum level due to safety and fuel consumption/GHG benefit concerns, we have decided to allow the soft top maximum level to be set to any level higher than the maximum speed governed by the VSL.  This approach will provide drivers with the ability to better navigate through traffic.  However, the agencies are requiring that manufacturers providing a soft top feature must design the system so it cannot be modified by the fleets and will not decrement the vehicle speed limit causing the vehicle to decelerate while the driver is operating a vehicle above the normal governed vehicle speed limit.  For example, if a manufacturer designs a vehicle speed limiter that has a normal governed speed limiter setting of 62 mph, and a "soft top" speed limiter value of 65 mph, the algorithm shall not cause the vehicle speed to decrement causing the vehicle to decelerate while the driver is operating the vehicle at a speed greater that 62 mph (between 62 and 65 mph).  The agencies are concerned that a forced deceleration when a driver is attempting to pass or maneuver could have an adverse impact on safety.
In using a soft top feature, a manufacturer will be required to provide to the agencies a functional description of the "soft top" control strategy including calibration values, the speed setting for both the hard limit and the soft top and the maximum time per day the control strategy could allow the vehicle to operate at the "soft top" speed limit at the time of certification.  This information will be used to derive a factor to discount the VSL input used in GEM modeling to determine the fuel consumption and GHG emissions performance of the vehicle.  We also agree with comments that VSLs should be adjustable so as not to potentially limit a vehicle's resale value.  However, manufacturers choosing the option to override the VSL after a specified number of miles would be required to discount the benefit of the VSL relative to the tractor's full lifetime miles.  The VSL discount benefits for using soft-top and expiration features must be calculated using Equation II-1.  Additional details regarding the derivation of the discounted equation are included in RIA Chapter 2.  The agencies are also requiring that any vehicle that has a "soft top" VSL to identify the use of the "soft top" VSL on the vehicle emissions label.
Equation II-1: Discounted Vehicle Speed Limiter Equation
VSL input for GEM = Expiration Factor * [Soft Top Factor* Soft Top VSL
+ (1-Soft Top Factor) * VSL] + (1-Expiration Factor)*65 mph
 In response to the comments about how the agencies will evaluate tampering, NHTSA and EPA have added a number of requirements in these final rules relating to the VSL control feature.  VSL control features should be designed so they cannot be easily overridden.  Manufacturers must ensure that the governed speed limit programmed into the VSL must also be verifiable through on-board diagnostic scanning tools, and must provide a description of the coding to identify the governed maximum speed limit and the expiration mileage both at the time of the initial vehicle certification and in-use.  The agencies believe both manufacturers and fleets should work toward maintaining the integrity of VSLs, and the agencies may conduct new-vehicle and in-use random audits to verify that inputs into GEM are accurate.
The agencies are aware that some fleets/owners make changes to vehicles, such as installing different diameter tires, changing the axle (final drive) ratio and transmission gearing, such that a vehicle could travel at speeds higher than the speed limited by its VSL.  Vehicles subject to FMCSA requirements must be in compliance with 49 CFR § 393.82.  The requirements apply to speedometers and states as follows:
      Each bus, truck, and truck-tractor must be equipped with a speedometer indicating vehicle speed 	in miles per hour and/or kilometers per hour. The speedometer must be accurate to within plus or minus 8 km/hr (5 mph) at a speed of 80 km/hr (50 mph).
To facilitate adjustments for component changes affecting vehicle speed, manufacturers should provide a fleet/owner with the means to do so unless the adjustments would affect the VSL setting or operation.
 DTNA and ATA additionally requested that the agencies ensure that any VSL provisions adopted under the GHG emissions and fuel efficiency rules align with existing NHTSA standards.  The agencies agree and note that there are no existing standards for a VSL outside of this current rulemaking activity.  However, NHTSA has announced its intent to publish a proposal in 2012 for a VSL.  While both agencies have taken steps to avoid potential conflicts between the rulemaking being finalized today for fuel consumption and GHG emissions and the anticipated safety rulemaking, different conclusions may be reached in a safety-based rulemaking on VSLs, particularly in the approach to specifying soft top parameters and VSL expiration.
Defined Vehicle Configurations in the GEM
As discussed above, the agencies are adopting methodologies that manufacturers will use to quantify the values input into the GEM for these factors affecting truck efficiency:  Coefficient of Drag, Tire Rolling Resistance Coefficient, Weight Reduction, Vehicle Speed Limiter, and Extended Idle Reduction Technology.  The other aspects of the vehicle configuration are fixed within the model and are not varied for the purpose of compliance.  The defined inputs include the tractor-trailer combination curb weight, payload, engine characteristics, and drivetrain for each vehicle type, and others.
Vehicle Drive Cycles
The simulation model (GEM) uses various inputs to characterize a vehicle's configuration (such as weight, aerodynamics, and rolling resistance) and predicts how the vehicle would behave on the road when it follows a driving cycle (vehicle speed versus time).  As noted by the 2010 NAS Report, the choice of a drive cycle used in compliance testing has significant consequences on the technology that will be employed to achieve a standard as well as the ability of the technology to achieve real world reductions in emissions and improvements in fuel consumption.  Manufacturers naturally will design vehicles to ensure they satisfy regulatory standards.  An ill-suited drive cycle for a regulatory category could encourage GHG emissions and fuel consumption technologies which satisfy the test but do not achieve the same benefits in use.  For example, requiring all trucks to use a constant speed highway drive cycle will drive significant aerodynamic improvements.  However, in the real world a combination tractor used for local delivery may spend little time on the highway, reducing the benefits achieved by this technology.  In addition, the extra weight of the aerodynamic fairings will actually penalize the GHG and fuel consumption performance in urban driving and may reduce the freight carrying capability. The unique nature of the kinds of CO2 emissions control and fuel consumption technology means that the same technology can be of benefit during some operation but cause a reduced benefit under other operation.  To maximize the GHG emissions and fuel consumption benefits and avoid unintended reductions in benefits, the drive cycle should focus on promoting technology that produces benefits during the primary operation modes of the application.  Consequently, drive cycles used in GHG emissions and fuel consumption compliance testing should reasonably represent the primary actual use, notwithstanding that every truck has a different drive cycle in-use.
The agencies proposed a modified version of the California ARB Heavy Heavy-duty Truck 5 Mode Cycle, using the basis of three of the cycles which best mirror Class 7 and 8 combination tractor driving patterns, based on information from EPA's MOVES model during the NPRM.  The key advantage of the California ARB 5 mode cycle is that it provides the flexibility to use several different modes and weight the modes to fit specific truck application usage patterns.  For proposal, EPA analyzed the five cycles and found that some modifications to the modes were to allow sufficient flexibility in weightings.  The agencies proposed the use of the Transient mode, as defined by California ARB, because it broadly covers urban driving.  The agencies also proposed altered versions of the High Speed Cruise and Low Speed Cruise modes which reflected only constant speed cycles at 65 mph and 55 mph respectively. The three cycles that were proposed were the ARB transient cycle, a 55 mph steady state cruise, and a 65 mph steady state cruise.
The agencies received comment from NACAA recommending an increase in the high speed cruise cycle speed from the proposed value of 65 mph to 75 mph because trucks travel at higher speeds.  The agencies analyzed the urban and rural interstate truck speed limits in each state to determine the national average truck speed limit.  State interstate speed limits for trucks vary between 55 and 75 mph, depending on the state.  Based on this information, the national median truck speed limit is 65 mph.  The agencies also analyzed the national average truck speed limit weighted by VMT for each state based on VMT data by state from the Federal Highway Administration as described in RIA section 3.4.2.  Based on this information, the national average VMT-weighted truck speed limit is 63 mph.  The agencies continue to believe that the appropriate high speed cruise speed should be set at the national average truck speed limit to appropriately balance the evaluation of technologies such as aerodynamics, but not overstate the benefits of these technologies.  Therefore, the agencies are adopting as proposed a speed of 65 mph for the high speed cruise cycle.
The agencies also received comments from Allison which disagreed with proposed drive cycles for combination tractors because they did not account for external factors such as grades, wind, traffic condition, etc.  They also believe that the acceleration rates are too low.  The agencies recognize that the proposed drive cycles do not incorporate the external factors described by Allison.  Parallel to the approach used to evaluate light-duty vehicles, the drive cycles do not incorporate either grade or wind which can be difficult to simulate in chassis dynamometer cells.  In the final rules, the agencies are defining an approach that manufacturers may take to evaluate their aerodynamic packages in a wind-averaged condition and use a modified Cd value in GEM.  Similarly, the agencies are adopting provisions for the innovative technology demonstration that allows for the use of on-road testing which includes grades for technologies whose benefits are reflected with grade.  Lastly, the agencies' final drive cycles for highway operation contain a constant speed, as proposed.  The acceleration and deceleration rates are only used to bring the vehicle to the cruising speed and the CO2 emissions and fuel consumption from these portions of the drive cycle are not included in the composite emissions and fuel consumption results.  The agencies did not include the speed dithering, which is representative of actual driving and traffic conditions, in the proposed constant speed portion of the cycles because the dithering does not provide any additional distinction between technologies but only added complexity to the cycle.  The agencies believe this approach is still appropriate for the final action.
Allison referred the agencies to the Oak Ridge National Laboratory and SmartWay program to review the amount of time long-haul vehicles spend on the highway.  They believe the steady state highway speeds are overestimated.  Data provided by Allison indicates that day cabs spend only 14 percent of miles traveling at speeds greater than 60 mph.  NHTSA and EPA recognize that there is a variation in the amount of miles day cabs travel under different operations.  As described above, the agencies are adopting an approach where tractors which operate like vocational vehicles will be treated as such in the HD program.  Thus, these day cabs will have a drive cycle weighting representative of vocational vehicles with more weighting on the transient operation and less on the highway speed operation.
For proposal, EPA and NHTSA relied on the EPA MOVES analysis of Federal Highway Administration data to develop the mode weightings to characterize typical operations of heavy-duty trucks, per Table II-9 below.  A detailed discussion of drive cycles is included in RIA Chapter 3.  The agencies are adopting the proposed drive cycle weightings for combination tractors.
Table II-9: Drive Cycle Mode Weightings

Transient
55 mph Cruise
65 mph Cruise
Day Cabs
19%
17%
64%
Sleeper Cabs
5%
9%
86%

Empty Weight and Payload
The total weight of the tractor-trailer combination is the sum of the tractor curb weight, the trailer curb weight, and the payload.  The total weight of a truck is important because it in part determines the impact of technologies, such as rolling resistance, on GHG emissions and fuel consumption.  In this final action, the agencies are specifying each of these aspects of the vehicle, as proposed.
In use, trucks operate at different weights at different times during their operations.  The greatest freight transport efficiency (the amount of fuel required to move a ton of payload) would be achieved by operating trucks at the maximum load for which they are designed all of the time.  However, logistics such as delivery demands which require that trucks travel without full loads, the density of payload, and the availability of full loads of freight limit the ability of trucks to operate at their highest efficiency all the time.  M.J. Bradley analyzed the Truck Inventory and Use Survey and found that approximately 9 percent of combination tractor miles travelled empty, 61 percent are "cubed-out" (the trailer is full before the weight limit is reached), and 30 percent are "weighed out" (operating weight equal 80,000 pounds which is the gross vehicle weight limit on the Federal Interstate Highway System or greater than 80,000 pounds for vehicles traveling on roads outside of the interstate system).
As described above, the amount of payload that a tractor can carry depends on the category (or GVWR and GCWR) of the vehicle.  For example, a typical Class 7 tractor can carry less payload than a Class 8 tractor.  For proposal, the agencies used the Federal Highway Administration Truck Payload Equivalent Factors using Vehicle Inventory and Use Survey (VIUS) and Vehicle Travel Information System data to determine the proposed payloads.  FHWA's results found that the average payload of a Class 8 truck ranged from 36,247 to 40,089 pounds, depending on the average distance travelled per day.  The same results found that Class 7 trucks carried between 18,674 and 34,210 pounds of payload also depending on average distance travelled per day. Based on this data, the agencies are proposed to prescribe a fixed payload of 25,000 pounds for Class 7 tractors and 38,000 pounds for Class 8 tractors for their respective test procedures. The agencies proposed a common payload for Class 8 day cabs and sleeper cabs as predefined GEM input because the data available do not distinguish based on type of Class 8 tractor.  These payload values represent a heavily loaded trailer, but not maximum GVWR, since as described above the majority of tractors "cube-out" rather than "weigh-out."
The agencies developed the proposed tractor curb weight inputs from actual tractor weights measured in two of EPA's test programs and based on information from the manufacturers.  The proposed trailer curb weight inputs were derived from actual trailer weight measurements conducted by EPA and weight data provided to ICF International by the trailer manufacturers.  Details of the individual weight inputs by regulatory category, as shown in Table II-9, are included in RIA Chapter 3.
Table II-10: Combination Tractor Weights
                                  MODEL TYPE
                                    CLASS 8
                                    CLASS 8
                                    CLASS 8
                                    CLASS 8
                                    CLASS 8
                                    CLASS 8
                                    CLASS 7
                                    CLASS 7
                                    CLASS 7
                            Regulatory Subcategory
                             Sleeper Cab High Roof
                             Sleeper Cab Mid Roof
                             Sleeper Cab Low Roof
                               Day Cab High Roof
                               Day Cab  Mid Roof
                               Day Cab  Low Roof
                               Day Cab High Roof
                               Day Cab  Mid Roof
                               Day Cab Low Roof
                           Tractor Tare Weight (lbs)
                                    19,000
                                    18,750
                                    18,500
                                    17,500
                                    17,100
                                    17,000
                                    11,500
                                    11,100
                                    11,000
                             Trailer Weight (lbs)
                                    13,500
                                    10,000
                                    10,500
                                    13,500
                                    10,000
                                    10,500
                                    13,500
                                    10,000
                                    10,500
                                 Payload (lbs)
                                    38,000
                                    38,000
                                    38,000
                                    38,000
                                    38,000
                                    38,000
                                    25,000
                                    25,000
                                    25,000
                              Total Weight (lbs)
                                    70,500
                                    66,750
                                    67,000
                                    69,000
                                    65,100
                                    65,500
                                    50,000
                                    46,100
                                    46,500

The agencies received comments from UMTRI and ATA regarding the values assumed for the combination tractor weights.  UMTRI recommended using 80,000 pounds for the total weight for tractor-trailer combinations.  ATA, based on their analysis of the Federal Highway Administration's Long Term Pavement Database, recommended 5,000 to 10,000 pound payload for Class 7 tractors and 25,000 to 30,000 pounds for Class 8 tractors.  ATA also determined from the same database that 20 percent of tractor miles are empty, 67 percent cube-out, and 13 percent weigh-out.  The agencies are adopting the proposed tractor-trailer weights because the changes suggested by the commenters will not change the evaluation of the technologies included in this phase of the HD program. NHTSA and EPA will evaluate additional sources of weight information in future phases of the program.
Standardized Trailers
As proposed, NHTSA and EPA are adopting provisions so that the tractor performance in the GEM will be judged by assuming it is pulling a standardized trailer.  The agencies believe that an assessment of the tractor aerodynamics should be conducted using a tractor-trailer combination where the likely tractor trailer combination is known.  We believe this approach best reflects the impact of aerodynamic technologies in actual use, where tractors are designed and used with a trailer.  Therefore, the aerodynamic test procedures and GEM model approach for high roof tractors that are typically used with box trailers is being finalized based on the use of a standardized box trailer.  In a change from our proposal we are finalizing provisions to allow for low and mid roof trailers to be tested without a defined trailer.  GEM will continue to use an predefined typical trailer in assessing overall performance.  We are finalizing this change in response to comments from truck manufacturers which have convinced us that the range of trailer designs and loads (e.g. flat trailers carrying sheets of steel versus flat trailers carrying industrial equipment) can vary to such a large degree that specifying one particular trailer for aerodynamic assessment would not be appropriate and could potentially lead to tractor designs that while beneficial when used with the specified test trailer were actually harmful in-use when used with the wide range of potential trailers and load configurations.
In addition to assessing the tractor with a trailer, it is appropriate to adopt a standardized trailer used for testing, and to vary the standardized trailer by the regulatory category.  This is similar to the standardization of payload discussed above, as a way to reasonably reflect in-use operating conditions.  High roof tractors are optimally designed to pull box trailers.  The roof fairing on a tractor is the feature designed to minimize the height differential between the tractor and typical trailer to reduce the air flow disruption.  Low roof tractors are designed to carry flat bed or low-boy trailers.  Mid roof tractors are designed to carry tanker and bulk carrier trailers.  The agencies conducted a survey of tractor-trailer pairing in-use to evaluate the representativeness of this premise.  The survey of over 3,000 tractor-trailer combinations found that in 95 percent of the combination tractors the tractor's roof height was paired appropriately for the type of trailer that it was pulling.  The agencies also have evaluated the impact of pairing a low roof tractor with a box trailer in coastdown testing and found that the aerodynamic force increases by 20 percent over a high roof tractor pulling the same box trailer.  Therefore, drivers have a large incentive to use the appropriate matching to reduce their fuel costs.  However, the agencies recognize that in operation tractors sometimes pull trailers other than the type that it was designed to carry.  In this final action, the agencies are matching trailers to roof height for the GEM model assessment, as proposed.  As discussed above the aerodynamic test procedure for low and mid-roof tractors will be conducted without the use of a standardized trailer.  The other aspects of the test procedure such as empty trailer weight, location of payload, and tractor-trailer gap are being finalized for each regulatory subcategory to provide consistent test procedures. These provisions are identical to those proposed.
Standardized Drivetrain
The agencies' assessment of the current vehicle configuration process at the truck dealer's level is that the truck companies provide tools to specify the proper drivetrain matched to the buyer's specific circumstances.  These dealer tools allow a significant amount of customization for drive cycle and payload to provide the best specification for each individual customer.  The agencies are not seeking to disrupt this process.  Optimal drivetrain selection is dependent on the engine, drive cycle (including vehicle speed and road grade), and payload.  Each combination of engine, drive cycle, and payload has a single optimal transmission and final drive ratio.  As proposed, the agencies are specifying the engine's fuel consumption map, drive cycle, and payload; therefore, it makes sense to also specify the drivetrain that matches.
Engine Input to GEM for Tractors
As proposed, the agencies are defining the engine characteristics used in GEM, including the fuel consumption map which provides the fuel consumption at hundreds of engine speed and torque points.  If the agencies did not standardize the fuel map, then a tractor that uses an engine with emissions and fuel consumption better than the standards would require fewer vehicle reductions than those technically feasible reductions reflected in the final standards.  The agencies are finalizing two distinct fuel consumption maps for use in GEM.  The first fuel consumption map would be used in GEM for the 2014 through 2016 model years and represents an average engine which meets EPA's final 2014 model year engine CO2 emissions standards.  The same fuel map would be used for NHTSA's voluntary standards in the 2014 and 2015 model years, as well as its mandatory program in the 2016 model year.  A second fuel consumption map will be used beginning in 2017 model year and represents an engine which meets the 2017 model year CO2 emissions and fuel consumption standards and accounts for the increased stringency in the final MY 2017 standard.  The agencies have modified the 2017 MY fuel map used in GEM for the final rulemaking to address comments received.  Details regarding this change can be found in RIA Chapter 4.4.4.  Effectively there is no change in stringency of the tractor vehicle (not including the engine) and there is stability in the tractor vehicle (not including engine) standards for the full rulemaking period.  These inputs are appropriate given the separate regulatory requirement that Class 7 and 8 combination tractor manufacturers use only certified engines.
Heavy-Duty Engine Test Procedure for Engines Installed in Combination Tractors
The HD engine test procedure consists of two primary aspects  -  a duty cycle and a metric to evaluate the emissions and fuel consumption.
EPA proposed that the GHG emission standards for heavy-duty engines under the CAA would be expressed as g/bhp-hr while NHTSA's proposed fuel consumption standards under EISA, in turn, be represented as gal/100 bhp-hr.  The NAS panel did not specifically discuss or recommend a metric to evaluate the fuel consumption of heavy-duty engines.  However, as noted above they did recommend the use of a load-specific fuel consumption metric for the evaluation of vehicles.  An analogous metric for engines is the amount of fuel consumed per unit of work.  The g/bhp-hr metric is also consistent with EPA's current standards for non-GHG emissions for these engines.  The agencies did not receive any adverse comments related to the metrics for HD engines; therefore, we are adopting the metrics as proposed.
EPA's criteria pollutant standards for engines currently require that manufacturers demonstrate compliance over the transient FTP cycle; over the steady-state SET procedure; and during not-to-exceed testing.  EPA created this multi-layered approach to criteria emissions control in response to engine designs that optimized operation for lowest fuel consumption at the expense of very high criteria emissions when operated off the regulatory cycle.  EPA's use of multiple test procedures for criteria pollutants helps to ensure that manufacturers calibrate engine systems for compliance under all operating conditions.  We are not concerned if off-cycle manufacturers further calibrate these designs to give better in-use fuel consumption while maintaining compliance with the criteria emissions standards as such calibration is entirely consistent with the goals of our joint program.  Further, we believe that setting standards based on both transient and steady-state operating conditions for all engines could lead to undesirable outcomes.  With regard to GHG and fuel consumption control, the agencies believe it is more appropriate to set standards based on a single test procedure, either the Heavy-duty FTP or SET, depending on the primary expected use of the engine.
It is critical to set standards based on the most representative test cycles in order for performance in-use to obtain the intended (and feasible) air quality benefits.  Tractors spend the majority of their operation at steady state conditions, and will obtain in-use benefit of technologies such as turbocompounding and other waste heat recovery technologies during this kind of typical engine operation.  Turbocompounding is a very effective approach to lower fuel consumption under steady driving conditions typified by combination tractor trailer operation and is well reflected in testing over the SET test procedure.  However, when used in driving typified by transient operation as we expect for vocational vehicles and as is represented by the Heavy-duty FTP, turbocompounding shows very little benefit.  Setting an emission standard based on the Heavy-duty FTP for engines intended for use in combination tractor trailers could lead manufacturers to not apply turbocompounding even though it can be a highly cost effective means to reduce GHG emissions and lower fuel consumption.
The agencies proposed that engines installed in tractors demonstrate compliance with the CO2 emissions and fuel consumption standards over the SET cycle.  Commenters such as Cummins, Bosch, Daimler, and Honeywell supported the proposed approach.  ACEEE recommended adopting a new test cycle, such as the World Harmonized Duty Cycle which was developed using newer data, to evaluate HD engines.  Daimler also supported the WHDC for future phases of the program.  The agencies continue to believe the important issues and technical work related to setting new criteria pollutant emissions standards appropriate for the World Harmonized Duty Cycle are significant and beyond the scope of this rulemaking.  Therefore, the agencies are adopting the SET cycle to evaluate CO2 emissions and fuel consumption of HD engines installed in tractors, as proposed.
The current non-GHG emissions engine test procedures also require the development of regeneration emission rates and frequency factors to account for the emission changes during a regeneration event (40 CFR 86.004-28).  EPA and NHTSA proposed not to include these emissions from the calculation of the compliance levels over the defined test procedures.  Cummins and Daimler supported this approach and stated there already exist sufficient incentives for manufacturers to limit regeneration frequency.  Conversely, Volvo opposed the omission of IRAF requirements for CO2 emissions because emissions from regeneration can be a significant portion of the expected improvement and a significant variable between manufacturers.
For proposal, we considered including regeneration in the estimate of fuel consumption and GHG emissions and decided not to do so for two reasons.  First, EPA's existing criteria emission regulations already provide a strong motivation to engine manufacturers to reduce the frequency and duration of infrequent regeneration events.  The very stringent 2010 NOX emission standards cannot be met by engine designs that lead to frequent and extend regeneration events.  Hence, we believe engine manufacturers are already reducing regeneration emissions to the greatest degree possible.  In addition to believing that regenerations are already controlled to the extent technologically possible, we believe that attempting to include regeneration emissions in the standard setting could lead to an inadvertently lax emissions standard.  In order to include regeneration and set appropriate standards, EPA and NHTSA would have needed to project the regeneration frequency and duration of future engine designs in the timeframe of this program.  Such a projection would be inherently difficult to make and quite likely would underestimate the progress engine manufacturers will make in reducing infrequent regenerations.  If we underestimated that progress, we would effectively be setting a more lax set of standards than otherwise would be expected.  Hence in setting a standard including regeneration emissions we faced the real possibility that we would achieve less effective CO2 emissions control and fuel consumption reductions than we will achieve by not including regeneration emissions.  Therefore, the agencies are finalizing an approach as proposed which does not include the regenerative emissions.
Chassis-based Test Procedure
In the proposal, the agencies considered proposing a chassis-based vehicle test to evaluate Class 7 and 8 tractors based on a laboratory test of the engine and vehicle together.  A "chassis dynamometer test" for heavy-duty vehicles would be similar to the Federal Test Procedure used today for light-duty vehicles.
However, the agencies decided not to propose the use of a chassis test procedure to demonstrate compliance for tractor standards due to the significant technical hurdles to implementing such a program by the 2014 model year.  The agencies recognize that such testing requires expensive, specialized equipment that is not yet widespread within the industry.  The agencies have only identified approximately 11 heavy-duty chassis sites in the United States today and rapid installation of new facilities to comply with model year 2014 is not possible.
In addition, and of equal if not greater importance, because of the enormous numbers of truck configurations that have an impact on fuel consumption, we do not believe that it would be reasonable to require testing of  many combinations of tractor model configurations on a chassis dynamometer.  The agencies evaluated the options available for one tractor model (provided as confidential business information from a truck manufacturer) and found that the company offered three cab configurations, six axle configurations, five front axles, 12 rear axles, 19 axle ratios, eight engines, 17 transmissions, and six tire sizes  -  where each of these options could impact the fuel consumption and CO2 emissions of the tractor.  Even using representative grouping of tractors for purposes of certification, this presents the potential for many different combinations that would need to be tested if a standard was adopted based on a chassis test procedure.
The agencies received comments from ACEEE and UCS supporting a full vehicle testing approach, but recognizing the difficulties in doing this in the first phase of the HD program. The agencies maintain that the full vehicle testing on chassis dynamometers is not feasible in this rulemaking, although we believe such an approach is likely to be appropriate in the future, if more testing facilities become available and if the agencies are able to address the complexity of tractor configurations issue described above.
Summary of Flexibility and Credit Provisions for Tractors and Engine Used in These Tractors
EPA and NHTSA are finalizing four flexibility provisions specifically for heavy-duty tractor and engine manufacturers, as discussed in Section IV below.  These are an averaging, banking and trading program for emissions and fuel consumption credits, as well as provisions for early credits, advanced technology credits, and credits for innovative vehicle or engine technologies which are not included as inputs to the GEM or are not demonstrated on the engine SET test cycle.  With the exception of the advanced technology credits, credits generated under these provisions can only be used within the same averaging set which generated the credit (for example, credits generated by HD engines used in tractors can only be used by HD engines).  EPA is also adopting a N2O emission credit program, as described in Section IV below.
Deferral of Standards for Tractor and Engine Manufacturing Companies That Are Small Businesses
EPA and NHTSA are not adopting  greenhouse gas emissions and fuel consumption standards for small tractor or engine manufacturers meeting the Small Business Administration (SBA) size criteria of a small business as described in 13 CFR 121.201.  The agencies will instead consider appropriate GHG and fuel consumption standards for these entities as part of a future regulatory action. This includes both U.S.-based and foreign small volume heavy-duty tractor and engine manufacturers.
The agencies have identified two entities that fit the SBA size criterion of a small business. The agencies estimate that these small entities comprise less than 0.5 percent of the total heavy-duty combination tractors in the United States based on Polk Registration Data from 2003 through 2007, and therefore that the exemption will have a negligible impact on the GHG emissions and fuel consumption improvements from the final standards.
To ensure that the agencies are aware of which companies would be exempt, we are requiring that such entities submit a declaration to EPA and NHTSA containing a detailed written description of how that manufacturer qualifies as a small entity under the provisions of 13 CFR 121.201.
Heavy-Duty Pickup Trucks and Vans
The primary elements of the EPA and NHTSA programs for complete HD pickups and vans are presented in this section.  These provisions also cover incomplete HD pickups and vans that are sold by vehicle manufacturers as cab-chassis (chassis-cab, box-delete, bed-delete, cut-away van) vehicles, as discussed in detail in Section V.B(1)(e).  Section II.C(1) explains the form of the CO2 and fuel consumption standards, the  numerical levels for those standards, and the approach to phasing in the standards over time.  The  measurement procedure for determining compliance is discussed in Section II.C(2), and the EPA and NHTSA compliance programs are discussed in Section II.C(3).  Sections II.C(4) discusses implementation flexibility provisions.  Section II.E discusses additional standards and provisions for N2O and CH4 emissions, for impacts from vehicle air conditioning, and for ethanol-fueled and electric vehicles.
What Are the Levels and Timing of HD Pickup and Van Standards?
Vehicle-Based Standards
About 90 percent of Class 2b and 3 vehicles are pickup trucks, passenger vans, and work vans that are sold by the original equipment manufacturers as complete vehicles, ready for use on the road.  In addition, most of these complete HD pickups and vans are covered by CAA vehicle emissions standards for criteria pollutants today (i.e., they are chassis tested similar to light-duty), expressed in grams per mile.  This distinguishes this category from other, larger heavy-duty vehicles that typically have only the engines covered by CAA engine emission standards, expressed in grams per brake horsepower-hour.  As a result, Class 2b and 3 complete vehicles share much more in common with light-duty trucks than with other heavy-duty vehicles.
Three of these commonalities are especially significant: (1) over 95 percent of the HD pickups and vans sold in the United States are produced by Ford, General Motors, and Chrysler  -  three companies with large light-duty vehicle and light-duty truck sales in the United States,  (2) these companies typically base their HD pickup and van designs on higher sales volume light-duty truck platforms and technologies, often incorporating new light-duty truck design features into HD pickups and vans at their next design cycle, and (3) at this time most complete HD pickups and vans are certified to vehicle-based rather than engine-based EPA standards.  There is also the potential for substantial GHG and fuel consumption reductions from vehicle design improvements beyond engine changes (such as through optimizing aerodynamics, weight, tires, and accessories), and the manufacturer is generally responsible for both engine and vehicle design.  All of these factors together suggest that it is appropriate and reasonable to set standards for the vehicle as a whole, rather than to establish separate engine and vehicle GHG and fuel consumption standards, as is being done for the other heavy-duty categories.  This approach for complete vehicles is consistent with Recommendation 8-1 of the NAS Report, which encourages the regulation of "the final stage vehicle manufacturers since they have the greatest control over the design of the vehicle and its major subsystems that affect fuel consumption."  There was consensus in the public comments supporting this approach.
Weight-Based Attributes
In setting heavy-duty vehicle standards it is important to take into account the great diversity of vehicle sizes, applications, and features.  That diversity reflects the variety of functions performed by heavy-duty vehicles, and this in turn can affect the kind of technology that is available to control emissions and reduce fuel consumption, and its effectiveness.  EPA has dealt with this diversity  in the past by making weight-based distinctions where necessary, for example in setting HD vehicle standards that are different for vehicles above and below 10,000 lb GVWR, and in defining different standards and useful life requirements for light-, medium-, and heavy-heavy-duty engines.  Where appropriate, distinctions based on fuel type have also been made, though with an overall goal of remaining fuel-neutral.
The joint EPA GHG and NHTSA fuel economy rules for light-duty vehicles accounted for vehicle diversity in that segment by basing standards on vehicle footprint (the wheelbase times the average track width).  Passenger cars and light trucks with larger footprints are assigned numerically higher target levels for GHGs and numerically lower target levels for fuel economy in acknowledgement of the differences in technology as footprint gets larger, such that vehicles with larger footprints have an inherent tendency to burn more fuel and emit more GHGs per mile of travel.  Using a footprint-based attribute to assign targets also avoids interfering with the ability of the market to offer a variety of products to maintain consumer choice.
In developing this rulemaking, the agencies emphasized creating a program structure that would achieve reductions in fuel consumption and GHGs based on how vehicles are used and on the work they perform in the real world, consistent with the NAS report recommendations to be mindful of HD vehicles' unique purposes.  Despite the HD pickup and van similarities to light-duty vehicles, we believe that the past practice in EPA's heavy-duty program of using weight-based distinctions in dealing with the diversity of HD pickup and van products is more appropriate than using vehicle footprint.  Weight-based measures such as payload and towing capability are key among the things that characterize differences in the design of vehicles, as well as differences in how the vehicles will be used. Vehicles in this category have a wide range of payload and towing capacities.  These weight-based differences in design and in-use operation are the key factors in evaluating technological improvements for reducing CO2 emissions and fuel consumption.  Payload has a particularly important impact on the test results for HD pickup and van emissions and fuel consumption, because testing under existing EPA procedures for criteria pollutants is conducted with the vehicle loaded to half of its payload capacity (rather than to a flat 300 lb as in the light-duty program), and the correlation between test weight and fuel use is strong.
Towing, on the other hand, does not directly factor into test weight as nothing is towed during the test.  Hence only the higher curb weight caused by heavier truck components would play a role in affecting measured test results.  However towing capacity can be a significant factor to consider because HD pickup truck towing capacities can be quite large, with a correspondingly large effect on design.
We note too that, from a purchaser perspective, payload and towing capability typically play a greater role than physical dimensions in influencing purchaser decisions on which heavy-duty vehicle to buy.  For passenger vans, seating capacity is of course a major consideration, but this correlates closely with payload weight.
Although heavy-duty vehicles are traditionally classified by their GVWR, we do not believe that GVWR is the best weight-based attribute on which to base GHG and fuel consumption standards for this group of vehicles.  GVWR is a function of not only payload capacity but of vehicle curb weight as well; in fact, it is the simple sum of the two.  Allowing more GHG emissions from vehicles with higher curb weight tends to penalize lightweighted vehicles with comparable payload capabilities by making them meet more stringent standards than they would have had to meet without the weight reduction.  The same would be true for another common weight-based measure, the gross vehicle combined weight, which adds the maximum combined towing and payload weight to the curb weight.
Similar concerns about using weight-based attributes that include vehicle curb weight were raised in the EPA/NHTSA proposal for light-duty GHG and fuel economy standards: "footprint-based standards provide an incentive to use advanced lightweight materials and structures that would be discouraged by weight-based standards", and "there is less risk of `gaming' (artificial manipulation of the attribute(s) to achieve a more favorable target) by increasing footprint under footprint-based standards than by increasing vehicle mass under weight-based standards -- it is relatively easy for a manufacturer to add enough weight to a vehicle to decrease its applicable fuel economy target a significant amount, as compared to increasing vehicle footprint" (74 FR 49685, September 28, 2009).  The agencies believe that using payload and towing capacities as the weight-based attributes avoids the above-mentioned disincentive for the use of lightweighting technology by taking vehicle curb weight out of the standards determination.
After taking these considerations into account, EPA and NHTSA proposed to set standards for HD pickups and vans based on the proposed "work factor" attribute that combines vehicle payload capacity and vehicle towing capacity, in pounds, with an additional fixed adjustment for four-wheel drive (4wd) vehicles.  This adjustment accounts for the fact that 4wd, critical to enabling the many off-road heavy-duty work applications, adds roughly 500 lb to the vehicle weight.  There was consensus in the public comments supporting this attribute, and the agencies are adopting it as proposed.  Target GHG and fuel consumption standards will be determined for each vehicle with a unique work factor (analogous to a target for each discrete vehicle footprint in the light duty vehicle rules).  These targets will then be production weighted and summed to derive a manufacturer's annual fleet average standard for its heavy duty pickups and vans.  Widespread support for the proposed work factor-based approach to standards and fleet average approach to compliance was expressed in the comments we received.
To ensure consistency and help preclude gaming, we are finalizing the proposed provision that payload capacity be defined as GVWR minus curb weight, and towing capacity as GCWR minus GVWR.  For purposes of determining the work factor, GCWR is defined according to SAE Recommended Practice J2807 APR2008, GVWR is defined consistent with EPA's criteria pollutants program, and curb weight is defined as in 40 CFR 86.1803-01.  Based on analysis of how CO2 emissions and fuel consumption correlate to work factor, we believe that a straight line correlation is appropriate across the spectrum of possible HD pickups and vans, and that vehicle distinctions such as Class 2b versus Class 3 need not be made in setting standards levels for these vehicles.  This approach was supported by commenters.
We note that payload/towing-dependent gram per mile and gallon per 100 mile standards for HD pickups and vans parallel the gram per ton-mile and gallon per 1,000 ton-mile standards being finalized for Class 7 and 8 combination tractors and for vocational vehicles.  Both approaches account for the fact that more work is done, more fuel is burned, and more CO2 is emitted in moving heavier loads than in moving lighter loads.  Both of these load-based approaches avoid penalizing truck designers wishing to reduce GHG emissions and fuel consumption by reducing the weight of their trucks.  However, the sizeable diversity in HD work truck and van applications, which go well beyond simply transporting freight, and the fact that the curb weights of these vehicles are on the order of their payload capacities, suggest that setting simple gram/ton-mile and gallon/ton-mile standards for them is not appropriate.  Even so, we believe that our setting of payload-based standards for HD pickups and vans is consistent with the NAS Report's recommendation in favor of load-specific fuel consumption standards.  Again, commenters agreed with this approach to setting HD pickup and van standards.
These attribute-based CO2 and fuel consumption standards are meant to be relatively consistent from a stringency perspective.  Vehicles across the entire range of the HD pickup and van segment have their respective target values for CO2 emissions and fuel consumption, and therefore all HD pickups and vans will be affected by the standard.  With this  attribute-based standards approach, EPA and NHTSA believe there should be no significant effect on the relative distribution of vehicles with differing capabilities in the fleet, which means that buyers should still be able to purchase the vehicle that meets their needs.
Standards
The agencies are finalizing standards based on a technology analysis performed by EPA to determine the appropriate HD pickup and van standards.  This analysis, described in detail in RIA Chapter 2, considered:
the level of technology that is incorporated in current new HD pickups and vans,
the available data on corresponding CO2 emissions and fuel consumption for these vehicles,
technologies that would reduce CO2 emissions and fuel consumption and that are judged to be feasible and appropriate for these vehicles through the 2018 model year,
the effectiveness and cost of these technologies for HD pickup and vans,
projections of future U.S. sales for HD pickup and vans, and
forecasts of manufacturers' product redesign schedules.
Based on this analysis, EPA is finalizing the proposed CO2 attribute-based target standards shown in Figure II-2 and II-3, and NHTSA is finalizing the equivalent attribute-based fuel consumption target standards, also shown in Figure II-2 and II-3, applicable in model year 2018.  These figures also shows phase-in standards for model years before 2018, and their derivation is explained below, along with alternative implementation schedules to ensure equivalency between the EPA and NHTSA programs while meeting statutory obligations.  Also, for reasons discussed below, separate targets were proposed and are being established for gasoline-fueled (and any other Otto-cycle) vehicles and diesel-fueled (and any other Diesel-cycle) vehicles.  The targets will be used to determine the production-weighted standards that apply to the combined diesel and gasoline fleet of HD pickups and vans produced by a manufacturer in each model year.

Figure II-2: EPA CO2 Target Standards and NHTSA Fuel Consumption Target Standards for Diesel HD Pickups and Vans

Figure II-3: EPA CO2 Target Standards and NHTSA Fuel Consumption Target Standards for Gasoline HD Pickups and Vans
Described mathematically, EPA's and NHTSA's  target standards are defined by the following formulae:
EPA CO2 Target (g/mile) = [a x WF] + b
NHTSA Fuel Consumption Target (gallons/100 miles) =  [c x WF] + d
Where:
      WF =  Work Factor  =  [0.75 x  (Payload Capacity + xwd)] + [0.25 x Towing Capacity]
Payload Capacity = GVWR (lb)  -  Curb Weight (lb)
xwd  =  500 lb if the vehicle is equipped with 4wd, otherwise equals 0 lb
Towing Capacity =  GCWR (lb)  -   GVWR (lb)
Coefficients a, b, c, and d are taken from Table II-11 or Table II-12.
Table II-11: Coefficients for HD Pickup and Van Target Standards
Diesel Vehicles
                                                                     Model Year
                                                                              a
                                                                              b
                                                                              c
                                                                              d
                                                                           2014
                                                                         0.0478
                                                                            368
                                                                       0.000470
                                                                           3.61
                                                                           2015
                                                                         0.0474
                                                                            366
                                                                       0.000466
                                                                           3.60
                                                                           2016
                                                                         0.0460
                                                                            354
                                                                       0.000452
                                                                           3.48
                                                                           2017
                                                                         0.0445
                                                                            343
                                                                       0.000437
                                                                           3.37
                                                                 2018 and later
                                                                         0.0416
                                                                            320
                                                                       0.000409
                                                                           3.14
Gasoline Vehicles
Model Year
                                                                              a
                                                                              b
                                                                              c
                                                                              d
                                                                           2014
                                                                         0.0482
                                                                            371
                                                                       0.000542
                                                                           4.17
                                                                           2015
                                                                         0.0479
                                                                            369
                                                                       0.000539
                                                                           4.15
                                                                           2016
                                                                         0.0469
                                                                            362
                                                                       0.000528
                                                                           4.07
                                                                           2017
                                                                         0.0460
                                                                            354
                                                                       0.000518
                                                                           3.98
                                                                 2018 and later
                                                                         0.0440
                                                                            339
                                                                       0.000495
                                                                           3.81

Table II-12: Coefficients for NHTSA's First Alternative and EPA's Alternative HD Pickup and Van Target Standards
Diesel Vehicles
                                                                     Model Year
                                                                              a
                                                                              b
                                                                              c
                                                                              d
                                                                        2014[a]
                                                                         0.0478
                                                                            368
                                                                       0.000470
                                                                           3.61
                                                                        2015[a]
                                                                         0.0474
                                                                            366
                                                                       0.000466
                                                                           3.60
                                                                      2016-2018
                                                                         0.0440
                                                                            339
                                                                       0.000432
                                                                           3.33
                                                                2019 and later
                                                                         0.0416
                                                                            320
                                                                       0.000409
                                                                           3.14
Gasoline Vehicles
Model Year
                                                                              a
                                                                              b
                                                                              c
                                                                              d
                                                                        2014[a]
                                                                         0.0482
                                                                            371
                                                                       0.000542
                                                                           4.17
                                                                        2015[a]
                                                                         0.0479
                                                                            369
                                                                       0.000539
                                                                           4.15
                                                                      2016-2018
                                                                         0.0456
                                                                            352
                                                                       0.000513
                                                                           3.96
                                                                2019 and later
                                                                         0.0440
                                                                            339
                                                                       0.000495
                                                                           3.81
      Notes:
      [a] NHTSA standards will be voluntary in 2014 and 2015

These targets are based on a set of vehicle, engine, and transmission technologies assessed by the agencies and determined to be feasible and appropriate for HD pickups and vans in the 2014-2018 timeframe.  See Section III.B for a detailed analysis of these vehicle, engine and transmission technologies, including their feasibility, costs, and effectiveness in HD pickups and vans.
To calculate a manufacturer's HD pickup and van fleet average standard, the agencies are requiring that separate target curves be used for gasoline and diesel vehicles. The agencies estimate that in 2018 the target curves will achieve 15 and 10 percent reductions in CO2 and fuel consumption for diesel and gasoline vehicles, respectively, relative to a common baseline for current (model year 2010) vehicles.  An additional two percent reduction in GHGs will be achieved by the EPA program from a direct air conditioning leakage standard.  These reductions are based on the agencies' assessment of the feasibility of incorporating technologies (which differ significantly for gasoline and diesel powertrains) in the 2014-2018 model years, and on the differences in relative efficiency in the current gasoline and diesel vehicles.  The resulting reductions represent roughly equivalent stringency levels for gasoline and diesel vehicles, which is important in ensuring our  program maintains product choices available to vehicle buyers.
Cummins objected to setting separate diesel and gasoline vehicle standards, on the basis that it increases the burden for diesel engine manufacturers more than for gasoline engine manufacturers, and thereby could shift market share away from diesels.  EMA argued for fuel-neutrality based on historical precedent and the fact that GHGs emitted by one type of engine are no different than those emitted by another type of engine.  We believe that both engine types have roughly equivalent redesign burdens as evidenced by the feasibility and cost analysis in RIA Chapter 2.  Also, even though the emissions and fuel consumption reductions are expressed from a common diesel/gasoline baseline in these final rules, the actual starting base for diesels is at a lower level than for gasoline vehicles. Other industry commenters, including those with sizeable diesel sales, expressed general support for the standards.
Environmental groups and others commented that the proposed standards were not stringent enough, citing the heavy-duty vehicle NAS study finding that technologies such as hybridization are feasible.  However, in the ambitious timeframe we are focusing on for these rules, targeting as it does technologies implementable in the HD pickup and van fleet starting in 2014 and phasing in with normal product redesign cycles through 2018, our assessment shows that the standards we are establishing are appropriate.  More advanced technologies considered in the NAS report would be appropriate for consideration in future rulemaking activity.  Additional conventional technologies identified by commenters as promising in light-duty applications and potentially useful for HD applications are discussed in RIA Chapter 2.
The NHTSA fuel consumption target curves and the EPA GHG target curves are equivalent.  The agencies established the target curves using the direct relationship between fuel consumption and CO2 using conversion factors of 8,887 g CO2/gallon for gasoline and 10,180 g CO2/gallon for diesel fuel.
It is expected that measured performance values for CO2 will generally be equivalent to fuel consumption.  However, as explained below in Section II. E. (3) , EPA is finalizing a provision for manufacturers to use CO2 credits to help demonstrate compliance with N2O and CH4 emissions standards, by expressing any N2O and CH4 undercompliance in terms of their CO2-equivalent and applying the needed CO2 credits.   For test families that do not use this compliance alternative, the measured performance values for CO2 and fuel consumption will be equivalent because the same test runs and measurement data will be used to determine both values, and calculated fuel consumption will be based on the same conversion factors that are used to establish the relationship between the CO2 and fuel consumption target curves (8,887 g CO2/gallon for gasoline and 10,180 g CO2/gallon for diesel fuel).  For manufacturers that choose to use the EPA provision for CO2 credit use in demonstrating N2O and CH4 compliance, compliance with the CO2 standard will not be directly equivalent to compliance with the NHTSA fuel consumption standard.
 Implementation Plan
EPA Program Phase-in MY 2014-2018
EPA is finalizing the proposed provision that the GHG standards be phased in gradually over the 2014-2018 model years, with full implementation effective in the 2018 model year.  Therefore, 100 percent of a manufacturer's vehicle fleet will need to meet a fleet-average standard that will become increasingly more stringent each year of the phase-in period.  For both gasoline and diesel vehicles, this phase-in will be 15-20-40-60-100 percent in model years 2014-2015-2016-2017-2018, respectively.  These percentages reflect stringency increases from a baseline performance level for model year 2010, determined by the agencies based on EPA and manufacturer data.  Because these vehicles are not currently regulated for GHG emissions, this phase-in takes the form of target line functions for gasoline and diesel vehicles that become increasingly stringent over the phase-in model years.  These year-by-year functions have been derived in the same way as the 2018 function, by taking a percent reduction in CO2 from a common unregulated baseline.  For example, in 2014 the reduction for both diesel and gasoline vehicles will be 15% of the fully-phased-in reductions.  Figures II-2 and II-3, and Table II-11, reflect this phase-in approach.
EPA is also providing manufacturers with an optional alternative implementation schedule in model years 2016 through 2018, equivalent to NHTSA's  first alternative for standards that do not change over these model years, described below.  Under this option the phase-in will be 15-20-67-67-67-100 percent in model years 2014-2015-2016-2017-2018-2019, respectively.  Table II-12, above, provides the coefficients "a" and "b" for this manufacturer's alternative.  As explained below, this alternative will provide roughly equivalent overall CO2 reductions and fuel consumption improvements as the 15-20-40-60-100 percent phase-in.  In addition, as explained below, the stringency of this alternative was established by NHTSA such that a manufacturer with a stable production volume and mix over the model year 2016-2018 period could use Averaging, Banking and Trading to comply with either alternative and have a similar credit balance at the end of model year 2018.
Under the above-described alternatives, each manufacturer will need to demonstrate compliance with the applicable fleet average standard using that year's target function over all of its HD pickups and vans starting with its MY 2014 fleet of HD pickups and vans.  No comments were received in support of an alternative approach that EPA requested comment on, involving phasing in an annually increasing percentage of each manufacturer's sales volume.
 NHTSA Program Phase-in 2016 and Later
NHTSA is finalizing the proposed provision to allow manufacturers to select one of two fuel consumption standard alternatives for model years 2016 and later.  Manufacturers will select an alternative at the same time they submit the model year 2016 Pre-Certification Compliance Report; and, once selected, the alternative will apply for model years 2016 and later, and could not be reversed.  To meet the EISA statutory requirement for three years of regulatory stability, the first alternative will define a fuel consumption target line function for gasoline vehicles and a target line function for diesel vehicles that will not change for model years 2016 and later.  The  target line function coefficients are provided in Table II-12.
The second alternative will be equivalent to the EPA target line functions in each model year starting in 2016 and continuing afterwards.  Stringency of fuel consumption standards will increase gradually for the 2016 and later model years.  Relative to a model year 2010 unregulated baseline, for both gasoline and diesel vehicles, stringency will be 40, 60, and 100 percent of the 2018 target line function in model years 2016, 2017, and 2018, respectively.  The stringency of the target line functions in the first alternative for model years 2016-2017-2018-2019 is 67-67-67-100 percent, respectively, of the 2018 stringency in the second alternative.  The stringency of the first alternative was established so that a manufacturer with a stable production volume and mix over the model year 2016-2018 period, could use Averaging, Banking and Trading to comply with either alternative and have a similar credit balance at the end of model year 2018 under the EPA and NHTSA programs.
NHTSA Voluntary Standards Period
NHTSA is finalizing the proposed provision that manufacturers may voluntarily opt into the NHTSA HD pickup and van program in model years 2014 or 2015.  If a manufacturer elects to opt into the program, the program would become mandatory and the manufacturer would not be allowed to reverse this decision.  To opt into the program, a manufacturer must declare its intent to opt in to the program at the same time it submits the Pre-Certification Compliance Report.  See regulatory text for 49 CFR 535.8 for information related to the Pre-Certification Compliance Report.  If a manufacturer elects to opt into the program in 2014, the program would be mandatory for 2014 and 2015.  A manufacturer would begin tracking credits and debits beginning in the model year in which they opt into the program.  The handling of credits and debits would be the same as for the mandatory program.
For manufacturers that opt into NHTSA's HD pickup and van fuel consumption program in 2014 or 2015, the stringency would increase gradually each model year.  Relative to a model year 2010 unregulated baseline, for both gasoline and diesel vehicles, stringency would be 15-20 percent of the model year 2018 target line function (under the NHTSA second alternative) in model years 2014-2015, respectively.  The corresponding absolute standards targets levels are provided in Figure II-2 and II-3, and the accompanying equations.
What Are the HD Pickup and Van Test Cycles and Procedures?
EPA and NHTSA are finalizing the proposed provision that HD pickup and van testing be conducted using the same heavy-duty chassis test procedures currently used by EPA for measuring criteria pollutant emissions from these vehicles, but with the addition of the highway fuel economy test cycle (HFET) currently required only for light-duty vehicle GHG emissions and fuel economy testing.  Although the highway cycle driving pattern is identical to that of the light-duty test, other test parameters for running the HFET, such as test vehicle loaded weight, are identical to those used in running the current EPA Federal Test Procedure for complete heavy-duty vehicles.
The GHG and fuel consumption results from vehicle testing on the Light-duty FTP and the HFET will be weighted by 55 percent and 45 percent, respectively, and then averaged in calculating a combined cycle result.  This result corresponds with the data used to develop the  work factor-based CO2 and fuel consumption standards, since the data on the baseline and technology efficiency was also developed in the context of these test procedures.  The addition of the HFET and the 55/45 cycle weightings are the same as for the light-duty CO2 and CAFE programs, as we believe the real world driving patterns for HD pickups and vans are not too unlike those of light-duty trucks, and we are not aware of data specifically on these patterns that would lead to a different choice of cycles and weightings, nor did any commenters provide such data.  More importantly, we believe that the 55/45 weightings will provide for effective reductions of GHG emissions and fuel consumption from these vehicles, and that other weightings, even if they were to more precisely match real world patterns, are not likely to significantly improve the program results.
Another important parameter in ensuring a robust test program is vehicle test weight.  Current EPA testing for HD pickup and van criteria pollutants is conducted with the vehicle loaded to its Adjusted Loaded Vehicle Weight (ALVW), that is, its curb weight plus (1/2) of the payload capacity.  This is substantially more challenging than loading to the light-duty vehicle test condition of curb weight plus 300 pounds, but we believe that this loading for HD pickups and vans to (1/2) payload better fits their usage in the real world and will help ensure that technologies meeting the standards do in fact provide real world reductions.  The choice is likewise consistent with use of an attribute based in considerable part on payload for the standard.  We see no reason to set test load conditions differently for GHGs and fuel consumption than for criteria pollutants, and we are not aware of any new information (such as real world load patterns) since the ALVW was originally set this way that would support a change in test loading conditions, nor did any commenters provide such information.  We are therefore using ALVW for test vehicle loading in GHG and fuel consumption testing.
Additional provisions for our final testing and compliance program are provided in Section V.B.
How Are the HD Pickup and Van Standards Structured?
EPA and NHTSA are finalizing the proposed fleet average standards for new HD pickups and vans, based on a manufacturer's new vehicle fleet makeup.  In addition, EPA is finalizing proposed in-use standards that apply to the individual vehicles in this fleet over their useful lives.  The compliance provisions for these  fleet average and in-use standards for HD pickups and vans are largely based on the recently promulgated light-duty GHG and fuel economy program, as described in detail in the proposal.
Fleet Average Standards
In the programs we are finalizing, each manufacturer will have a GHG standard and a fuel consumption standard unique to its new HD pickup and van fleet in each model year, depending on the load capacities of the vehicle models produced by that manufacturer, and on the U.S.-directed production volume of each of those models in that model year.  Vehicle models with larger payload/towing capacities have individual targets at numerically higher CO2 and fuel consumption levels than lower payload/towing vehicles, as discussed in Section II.C(1).  The fleet average standard for a manufacturer is a production-weighted average of the work factor-based targets assigned to unique vehicle configurations within each model type produced by the manufacturer in a model year.
The fleet average standard with which the manufacturer must comply is based on its final production figures for the model year, and thus a final assessment of compliance will occur after production for the model year ends.  Because compliance with the fleet average standards depends on actual test group production volumes, it is not possible to determine compliance at the time the manufacturer applies for and receives an EPA certificate of conformity for a test group. Instead, at certification the manufacturer will demonstrate a level of performance for vehicles in the test group, and make a good faith demonstration that its fleet, regrouped by unique vehicle configurations within each model type, is expected to comply with its fleet average standard when the model year is over.  EPA will issue a certificate for the vehicles covered by the test group based on this demonstration, and will include a condition in the certificate that if the manufacturer does not comply with the fleet average, then production vehicles from that test group will be treated as not covered by the certificate to the extent needed to bring the manufacturer's fleet average into compliance.  As in the light-duty program, additional "model type" testing will be conducted by the manufacturer over the course of the model year to supplement the initial test group data.  The emissions and fuel consumption levels of the test vehicles will be used to calculate the production-weighted fleet averages for the manufacturer, after application of the appropriate deterioration factor to each result to obtain a full useful life value.  See generally 75 FR 25470-25472.
EPA and NHTSA do not currently anticipate notable deterioration of CO2 emissions and fuel consumption performance, and are therefore requiring that an assigned deterioration factor be applied at the time of certification: an additive assigned deterioration factor of zero, or a multiplicative factor of one will be used.  EPA and NHTSA anticipate that the deterioration factor may be updated from time to time, as new data regarding emissions deterioration for CO2 are obtained and analyzed.  Additionally, EPA and NHTSA may consider technology-specific deterioration factors, should data indicate that certain control technologies deteriorate differently than others.  See also 75 FR 25474.
In-Use Standards
Section 202(a)(1) of the CAA specifies that EPA set emissions standards that are applicable for the useful life of the vehicle.  The in-use standards that EPA is finalizing apply to individual vehicles.  NHTSA is not adopting in-use standards because they are not required under EISA, and because it is not currently anticipated that there will be any notable deterioration of fuel consumption.  For the EPA program, compliance with the in-use standard for individual vehicles and vehicle models will not impact compliance with the fleet average standard, which will be based on the production-weighted average of the new vehicles (as explained below).
EPA is finalizing the proposed provision that the in-use standards for HD pickups and vans be established by adding an adjustment factor to the full useful life emissions and fuel consumption results used to calculate the fleet average.  EPA is also finalizing the proposed provision that the useful life for these vehicles with respect to GHG emissions be set equal to their useful life for criteria pollutants:  11 years or 120,000 miles, whichever occurs first (40 CFR 86.1805-04(a)).
As discussed above, we are finalizing the proposed provision that certification test results obtained before and during the model year be used directly to calculate the fleet average emissions for assessing compliance with the fleet average standard. Therefore, this assessment and the fleet average standard itself do not take into account test-to-test variability and production variability that can affect measured in-use levels.  For this reason, EPA is finalizing the proposed adjustment factor for the in-use standard to provide some margin for production and test-to-test variability that could result in differences between the initial emission test results used to calculate the fleet average and emission results obtained during subsequent in-use testing.  EPA is finalizing the proposed provision that each model's in-use CO2 standard be the model-specific level used in calculating the fleet average, plus 10 percent.  This is the same as the approach taken for light-duty vehicle GHG in-use standards (See 75 FR 25473-25474).  No adverse comments were received on this proposed provision.
As it does now for heavy-duty vehicle criteria pollutants, EPA will use a variety of mechanisms to conduct assessments of compliance with the  in-use standards, including pre-production certification and in-use monitoring once vehicles enter customer service.  The full useful life in-use standards apply to vehicles that have entered customer service.  The same standards apply to vehicles used in pre-production and production line testing, except that deterioration factors are not applied.
What HD Pickup and Van Flexibility Provisions Are Being Established?
This program contains substantial flexibility in how manufacturers can choose to implement the EPA and NHTSA standards while preserving their timely benefits for the environment and energy security.  Primary among these flexibilities are the gradual phase-in schedule, alternative compliance paths, and corporate fleet average approach described above.  Additional flexibility provisions are described briefly here and in more detail in Section IV.
As explained in Section II.C(3),  we are finalizing the proposed provision that, at the end of each model year, when production for the model year is complete, a manufacturer calculate its production-weighted fleet average CO2 and fuel consumption.  Under this  approach, a manufacturer's HD pickup and van fleet that achieves a fleet average CO2 or fuel consumption level better than its standard will be allowed to generate credits.  Conversely, if the fleet average CO2 or fuel consumption level does not meet its standard, the fleet would incur debits (also referred to as a shortfall).
A manufacturer whose fleet generates credits in a given model year will have several options for using those credits to offset emissions from other HD pickups and vans. These options include credit carry-back, credit carry-forward, and credit trading.  These provisions exist in the 2012-2016 MY light-duty vehicle National Program, and similar provisions are part of EPA's Tier 2 program for light-duty vehicle criteria pollutant emissions, as well as many other mobile source standards issued by EPA under the CAA.  The manufacturer will be able to carry back credits to offset a deficit that had accrued in a prior model year and was subsequently carried over to the current model year, with a limitation on the carry-back of credits to three years, consistent with the light-duty program.  We are finalizing the proposed provision that, after satisfying any need to offset pre-existing deficits, a manufacturer may bank remaining credits for use in future years.  We are also finalizing the proposed provision that manufacturers may certify their HD pickup and van fleet a year early, in MY 2013, to generate credits against the MY 2014 standards.  This averaging, banking, and trading program for HD pickups and vans is discussed in more detail in Section IV.A.  For reasons discussed in detail in that section, we are not finalizing any credit transferability to or from other credit programs or averaging sets.
Consistent with the President's May 21, 2010 directive to promote advanced technology vehicles and with the agencies' respective statutory authorities, we are adopting flexibility provisions that parallel similar provisions adopted in the light-duty program.  These include credits for advance technology vehicles such as electric vehicles, and credits for innovative technologies that are shown by the manufacturer to provide GHG and fuel consumption reductions in real world driving, but not on the test cycle.  See Section IV.B.We believe that it is also appropriate to take steps to recognize the benefits of flexible-fueled vehicles (FFVs) and dedicated alternative-fueled vehicles based on the approach taken by EPA in the light-duty vehicle rule for later models years (2016 and later).  However, unlike in that rule, we do not believe it is appropriate to create a provision for additional credits similar to the 2012-2015 light-duty program because the HD sector does not have the incentives mandated in EISA for light-duty FFVs, and so has not relied on the existence of such credits in devising compliance strategies for the early model years of this program.  See  74 FR at 49531.  In fact, manufacturers have not in the past produced FFV heavy-duty vehicles.  On the other hand, we did seek comment on how to properly recognize the impact of the use of alternative fuels, and E85 in particular, in HD pickups and vans, including the proper accounting for alternative fuel use in FFVs in the real world.  See 75 FR at 74198.   FFV performance will be determined in the same way as for light-duty vehicles, with a 50-50 weighting of alternative and conventional fuel test results through MY 2015, and a manufacturer-determined weighting based on demonstrated fuel use in the real world after MY 2015 (defaulting to an assumption of 100 percent conventional fuel use).  See 75 FR at 25434. For dedicated alternative fueled vehicles, NHTSA will require that vehicles be tested with the alternative fuel, and a petroleum equivalent fuel consumption level be calculated based on the Petroleum Equivalency Factor (PEF) that is determined by the Department of Energy.
Class 2b-8 Vocational Vehicles
Heavy-duty vehicles serve a vast range of functions including service for urban delivery, refuse hauling, utility service, dump, concrete mixing, transit service, shuttle service, school bus, emergency, motor homes, and tow trucks to name only a small subset of the full range of vehicles.  The vehicles designed to serve these functions are as unique as the jobs they do.  They are vastly different in size, shape and function.  The agencies were unable to develop a specific vehicle definition based on the characteristics of these vehicles.  Instead at proposal, we proposed to define that Class 2b-8 vocational vehicles as all heavy-duty vehicles which are not included in the Heavy-duty Pickup Truck and Van or the Class 7 and 8 Tractor categories.  In effect, we said everything that is not a combination tractor or a pickup truck or van is a vocational truck.  We are finalizing that definition as proposed reflecting the same challenges we faced at proposal regarding defining the full range of heavy-duty vehicles.  As at proposal, recreational vehicles are included under EPA's standards but are not included under NHTSA's final standards. The agencies note that we are adding vocational tractors to the vocational vehicle category in the final rulemaking, as described above in Section II.B.
The agencies proposed that Class 4 pickup trucks although similar to Class 2b and 3 vehicles be included in the vocational vehicle category.  Comments from EMA, Cummins and Navistar supported the premise that Class 4 vehicles belong as part of the vocational vehicle program because they are specifically designed and engineered to meet vocational requirements.  They stated that components such as transmissions, axles, frames, and tires differ from the similar pickup truck and vans in the Class 2b and 3 market.  Given the consensus on this issue, the agencies are finalizing the proposed approach to classify Class 4 pickup trucks in the vocational vehicle category.
As mentioned in Section I, vocational vehicles undergo a complex build process.  Often an incomplete chassis is built by a chassis manufacturer with an engine purchased from an engine manufacturer and a transmission purchased from another manufacturer.  A body manufacturer purchases an incomplete chassis which is then completed by attaching the appropriate features to the chassis.
The diversity in the vocational vehicle segment can be primarily attributed to the variety of vehicle bodies rather than to the chassis.  For example, a body builder can build either a Class 6 bucket truck or a Class 6 delivery truck from the same Class 6 chassis.  The aerodynamic difference between these two vehicles due to their bodies will lead to different baseline fuel consumption and GHG emissions.  However, the baseline fuel consumption and emissions due to the components included in the common chassis (such as the engine, drivetrain, frame, and tires) will be the same between these two types of complete vehicles.
The agencies face difficulties in establishing the baseline CO2 and fuel consumption performance for the wide variety of complete vocational vehicles because of the very large number of vehicle types and the need to conduct testing on each of the vehicle types to establish the baseline. To establish standards for a complete vocational vehicle, it would be necessary to assess the potential for fuel consumption and GHG emissions improvement for each of these vehicle types and to establish standards for each vehicle type.  Because of the size and complexity of this task, the agencies judged it was not practical to regulate complete vocational vehicles for this first fuel consumption and GHG emissions program. To overcome the lack of baseline information from the different vehicle types and to still achieve improvements fuel consumption and GHG emissions, the agencies proposed to set standards for the chassis manufacturers of vocational vehicles (instead of the body builders) and the engine manufacturers.  Chassis manufacturers represent a limited number of companies as compared to body manufacturers, which are made up of a diverse set of companies that are typically small businesses.  These companies would need to be regulated if whole vehicle standards were established.
Similar to combination tractors, the agencies proposed to set separate vehicle and engine standards for vocational vehicles.  A number of comments were received on the proposal to regulate chassis and engine manufacturers.  The agencies received comments from DTNA supporting the proposal to regulate the chassis manufacturer.  While organizations like Cummins and ICCT expressed support for separate engine and vehicle standards; Navistar, Pew, and Volvo, in contrast, opposed separate engine and chassis standards, stating that separate engine standards disadvantages integrated truck/engine manufacturers and full vehicle standards should be required.  Volvo asked that the standards include an alternative integrated standard as well as complete vehicle modeling and testing beginning in 2017.  ACEEE and Sierra Club stated that the proposed standards and test procedures should move the agencies closer to full vehicle testing.
While the agencies understand that full vehicle standards would allow integrated truck/engine manufacturers additional technologies to comply with the regulation which are not available under the current program design  -  such as electrified accessories and weight reduction --  the agencies are finalizing separate standards for vocational vehicles that apply to chassis manufacturers and engine standards that apply to engine manufacturers.  The agencies continue to believe that it is not practical to regulate complete vocational vehicles for this first fuel consumption and GHG emissions program because of the size and complexity of the task associated with assessing the potential for fuel consumption and GHG emissions improvement for each type of vocational vehicle. Thus, the agencies are finalizing a set standards for the chassis manufacturers of vocational vehicles (instead of the body builders) and for the engine manufacturers.
In the NPRM, the agencies proposed vehicle standards based on the agencies' assessment of the availability of low rolling resistance tires that could be applied to vocational vehicles.  The agencies considered the possibility of including other technologies in determining the proposed stringency of the vocational vehicle standards, such as aerodynamic improvements, but as discussed in the NPRM, tentatively concluded that such improvements would not be appropriate for basing vehicle standard stringency in this phase of the rulemaking.  For example, the aerodynamics of a recovery vehicle are impacted significantly by the equipment such as the arm located on the exterior of the truck.  The agencies found little opportunity to improve the aerodynamics of the equipment on the truck.  The agencies also evaluated the aerodynamic opportunities discussed in the NAS report.  The panel found that there was minimal fuel consumption reduction opportunity through aerodynamic technologies for bucket trucks, transit buses, and refuse trucks primarily due to the low vehicle speed in normal operation.  The panel did report that there are opportunities to reduce the fuel consumption of straight trucks by approximately 1 percent for trucks which operate at the average speed typical of a pickup and delivery truck (30 mph), although the opportunity is greater for trucks which operate at higher speeds.  Thus, the proposed vocational vehicle standards for fuel consumption and GHG emissions were based solely on the use of low rolling resistance tires.
The agencies received comments from the Motor Equipment Manufacturers Association, Eaton, NRDC, NESCAUM, NACAA, ACEEE, ICCT, Navistar, Arvin Meritor, the Union of Concerned Scientists and others that technologies such as idle reduction, advanced transmissions, advanced drivetrains, weight reduction, hybrid powertrains, and improved auxiliaries provide opportunities to reduce fuel consumption from vocational vehicles.  Commenters asked that the agencies establish regulations that would require the incorporation of these technologies.
The agencies assessed these technologies and have concluded that they may have the potential to reduce fuel consumption and GHG emissions, but the agencies have not been able to estimate baseline fuel consumption and GHG emissions levels for each type of vocational vehicle and for each type of technology, given the wide variety of models and uses of vocational vehicles.  For example, idle reduction technologies such as APUs and cabin heaters can reduce workday idling associated with vocational trucks.  However, characterizing idling activity for the vocational segment in order to quantify the benefits of idle reduction technology is complicated by the variety of duty cycles found in the sector.  Idling in school buses, fire trucks, pick-up trucks, delivery trucks, and other types of vocational vehicles varies significantly.  Given the great variety of duty cycles and operating conditions of vocational vehicles and the timing of these rules, it is not feasible at this time to establish an accurate baseline for the idle reduction technologies evaluated.  Similarly, for advanced drivetrains and advanced transmissions determining a baseline configuration, or a set of baseline configurations, is extremely difficult given the variety of trucks in this segment.  The agencies do not believe that we can legitimately base standard stringency on the use of technologies for which we cannot identify baseline configurations, because baseline emissions and fuel consumption are the benchmarks against which standards are developed.  For some technologies, such as weight reduction and improved auxiliaries  -  such as electrically driven power steering pumps and the vehicle's air conditioning system -- the need to limit technologies to those under the control of the chassis manufacturer restricted the agencies' options for incorporating the technologies into the final rules.  For example, lightweight components that are under the control of chassis manufacturers are limited to a very few components such as frame rails.  Considering the fuel efficiency and GHG emissions reduction benefits that will be achieved by finalizing these rules in the timeframe proposed, rather than delaying in order to gain enough information to include additional technologies, the agencies have decided to finalize standards that do not assume the use of these technologies and will consider incorporating them in a later action.
As the program progresses and the agencies gather more information, we expect to reconsider whether vocational vehicle standards for MYs 2019 and beyond should be based on the use of additional technologies besides low rolling resistance tires.
EPA is adopting CO2 standards and NHTSA is finalizing fuel consumption standards for manufacturers of chassis for new vocational vehicles and for manufacturers of heavy-duty engines installed in these vehicles.  The final heavy-duty engine standards for CO2 emissions and fuel consumption focus on potential technological improvements in fuel combustion and overall engine efficiency and those controls would achieve most of the emission reductions. Further reductions from the Class 2b-8 vocational vehicle itself are possible within the timeframe of these final regulations. Therefore, the agencies are also finalizing separate standards for vocational vehicles that will focus on additional reductions that can be achieved through improvements in vehicle tires.  The agencies' analyses, as discussed briefly below and in more detail later in this preamble and in the RIA Chapter 2, show that these final standards appear appropriate under each agency's respective statutory authorities. Together these standards are estimated to achieve reductions of up to 10 percent from most vocational vehicles.
EPA is also adopting standards to control N2O and CH4 emissions from Class 2b-8 vocational vehicles through controlling these GHG emissions from the HD engines.  The final heavy-duty engine standards for both N2O and CH4 and details of the standard are included in the discussion in Section II.E.1.b and II.E.2.b. EPA neither proposed nor is adopting air conditioning leakage standards applying to chassis manufacturers.
As discussed further below, the agencies are setting CO2 and fuel consumption standards for these chassis based on tire rolling resistance improvements and for the engines based on engine technologies.  The fuel consumption and GHG emissions impact of tire rolling resistance is impacted by the mass of the vehicle.  However, the impact of mass on rolling resistance is relatively small so the agencies proposed to aggregate several vehicle weight categories under a single category for setting the standards.  The agencies proposed to divide the vocational vehicle segment into three broad regulatory subcategories - Light Heavy-Duty (Class 2b through 5), Medium Heavy-Duty (Class 6 and 7), and Heavy Heavy-Duty (Class 8) which is consistent with the nomenclature used in the diesel engine classification. The agencies received comments supporting the division of vocational vehicles into three regulatory categories from DTNA.  The agencies also received comments from Bosch, Clean Air Task Force, and National Solid Waste Management Association supporting a finer resolution of vocational vehicle subcategories.  Their concerns include that the agencies' truck configuration in GEM is not representative of a particular vocational application, such as refuse trucks.  Another recommendation was to divide the category by both GVWR and by operational characteristics.  Upon further consideration, the agencies are finalizing as proposed three vocational vehicle subcategories because we feel this adequately balances simplicity while still obtaining reductions in this diverse segment.  Finer distinctions in regulatory subcategories would not change the technologies or reductions expected from the vocational vehicle category.  As the agencies move towards future heavy-duty fuel consumption and GHG regulations for post-2017 model years, we intend to gather GHG and fuel consumption data for specific vocational applications which could be used to establish application-specific standards in the future.
EPA received comments supporting the exclusion of recreational vehicles, emergency vehicles, school buses from the rulemaking.  The commenters argued that these individual vehicle types were small contributors to overall GHG emissions and that tires meeting their particular performance needs might not be available by 2014.  The agencies considered these comments and EPA has decided to finalize standards for these individual vehicle categories as we proposed.  NHTSA will continue to exempt recreational vehicles.  We have taken this decision reflecting that any individual vocational truck segment is likely to be a small contributor to overall fuel consumption and GHG emissions on its own.  Absent regulations for the vast majority of vehicles in this segment, our program will fall short of its goals.  Further since the proposal, the agencies have met with a number of tire manufacturers to better understand their expectations for product availability for the 2014 model year.  Based on our review of the information shared, we are convinced that tires with rolling resistance consistent with our final vehicle standards and meeting the full range of other performance characteristics desired in the vehicle market will be broadly available by the 2014 model year.
What Are the Vocational Vehicle and Engine CO2 and Fuel Consumption Standards and Their Timing?
In developing the final standards, the agencies have evaluated the current levels of emissions and fuel consumption, the kinds of technologies that could be utilized by manufacturers to reduce emissions and fuel consumption and the associated lead time, the associated costs for the industry, fuel savings for the consumer, and the magnitude of the CO2 and fuel savings that may be achieved.  After examining the possibility of vehicle improvements based on use of the technologies underlying the standards for Class 7/8 tractors, including improved aerodynamics, vehicle speed limiters, idle reduction technologies, tire rolling resistance, and weight reduction, as well as use of hybrid technologies, the agencies ultimately determined to base the final vehicle standards on performance of tires with superior rolling resistance.  For standards for diesel engines installed in vocational vehicles, the agencies examined performance of engine friction reduction, aftertreatment optimization, air handling improvements, combustion optimization, turbocompounding, and waste heat recovery, ultimately determining to based the final standards on the performance of all of the technologies except turbocompounding and waste heat recovery systems.  The agencies' evaluation indicates that these technologies, as described in Section III.C, are available today in the heavy-duty tractor and light-duty vehicle markets, but have very low application rates in the vocational market.  The agencies have analyzed the technical feasibility of achieving the CO2 and fuel consumption standards, based on projections of what actions manufacturers would be expected to take to reduce emissions and fuel consumption to achieve the standards, and believe that the standards are cost-effective and technologically feasible and appropriate within the rulemaking time frame.  EPA and NHTSA also present the estimated costs and benefits of the vocational vehicle standards in Section III.
Vocational Vehicle Chassis Standards
In the NPRM, the agencies defined tire rolling resistance as a frictional loss of energy, associated mainly with the energy dissipated in the deformation of tires under load that influences fuel efficiency and CO2 emissions.  Tires with higher rolling resistance lose more energy in response to this deformation, thus using more fuel and producing more CO2 emissions in operation, while tires with lower rolling resistance lose less energy, and save more fuel and CO2 emissions in operation.  Tire design characteristics (e.g., materials, construction, and tread design) influence durability, traction (both wet and dry grip), vehicle handling, ride comfort, and noise in addition to rolling resistance.
The agencies explained that a typical Low Rolling Resistance (LRR) tire's attributes, compared to a non-LRR tire, would include increased tire inflation pressure; material changes; and tire construction with less hysteresis, geometry changes (e.g., reduced height to width aspect ratios), and reduction in sidewall and tread deflection.  When a manufacturer applies LRR tires to a vehicle, they generally also make changes to the vehicle's suspension tuning and/or suspension design in order to maintain vehicle handling and ride comfort.
The agencies also explained that while LRR tires can be applied to vehicles in all MD/HD classes, they may have special potential for improving fuel efficiency and reducing CO2 emissions for vocational vehicles.  According to an energy audit conducted by Argonne National Lab, tires are the second largest contributor to energy losses of vocational vehicles, after engines.  Given this finding, the agencies considered the availability of LRR tires for vocational applications by examining the population of tires available, and concluded that there appeared to be few LRR tires for vocational applications.  The agencies suggested in the NPRM that this low number of LRR tires for vocational vehicles could be due in part to the fact that the competitive pressure to improve rolling resistance of vocational vehicle tires has been less than in the line haul tire market, given that line haul vehicles generally drive significantly more miles and therefore have significantly higher operating costs for fuel than vocational vehicles, and much greater incentive to improve fuel consumption. The small number of LRR tires for vocational vehicles may perhaps also be due in part to the fact that vocational vehicles generally operate more frequently on secondary roads, gravel roads and roads that have less frequent winter maintenance, which leads vocational vehicle buyers to value tire traction and durability more heavily than rolling resistance.  The agencies recognized that this provided an opportunity to improve fuel consumption and GHG emissions by creating a regulatory program that encourages improvements in tire rolling resistance for both line haul and vocational vehicles. The agencies proposed to base standards for all segments of HD vehicles on the use of LRR tires.  The agencies estimated that a 10 percent reduction in average tire rolling resistance would be attainable between model years 2010 and 2014 based on the tire development achievements over the last several years in the line haul truck market. This reduction in tire rolling resistance would correlate to a 2 percent reduction in fuel consumption as modeled by the GEM.
Summary of Comments
The agencies received many comments on the subject of tire rolling resistance.  Comments included suggestions for alternative test procedures; whether LRR tires should be applied to certain types of vocational vehicles and whether certain vehicles should be exempted from the vocational vehicle standards if the standards are based on the ability to use LRR tires (these particular comments are discussed in Section II.D of the preamble); the appropriateness of the proposed standards; and compliance issues (discussed below in Section II.D.2.b.
Regarding whether LRR tires should be applied to certain types of vocational vehicles, the agencies received many comments from stakeholders, such as Daimler Trucks North America, Fire Apparatus Manufacturers Association (FAMA), International Association of Fire Chiefs, National Ready Mix, National Solid Wastes Management Association (NSWMA), Spartan Motors, National Automobile Dealers Association, among others.  There were comments regarding applicability of low rolling resistance tires to vocational vehicles based on LRR tire availability, suitability of the tires for the applications, fuel consumption and GHG emissions benefits and the appropriateness of standards. Many of these commenters focused particularly on the whether LRR tires would compromise the capability of emergency vehicles.  Comments related to the capability of emergency vehicles are discussed and responded to in greater detail above in Section II.D.
Regarding whether LRR tires are available in the market for certain vocational vehicles and whether the vocational vehicle standards were therefore appropriate and feasible, both Ford and AAPC stated that the proposed model-based requirement for Class 2b-8 vocational chassis appeared to require tires with rolling resistance values of approximately 8.0-8.1 kg/metric ton or better, and that limited data available for smaller diameter tires, such as LT tires used on many light heavy duty trucks and vans, suggested that there exist few if any choices for tires that would comply.  Given this concern about the availability of compliant tires, particularly in the case of tires smaller than 22.5", during the proposed regulatory time frame, AAPC and Ford requested revisions to the requirement, or the modeling method, to establish different standards for vehicles that use different tire classes, with separate requirements for LT tires, 19.5" tires, and 22.5" tires.  AAPC argued that standards should be set based on data collected on high volume in-use tires, and that they should be set at a level that ensures the availability of multiple compliant tires.  Oshkosh went further and stated that the agencies did not even need to use GEM for determining compliance with the vocational standards, since all the variables other than tire RRC are predefined inputs, and therefore the agencies could simply set a standard for tires on vocational vehicles that required them to have rolling resistance values lower than 8.0 kg/metric ton.
Summary of Research Done Since the Notice of Proposed Rulemaking
Since the NPRM, the agencies have conducted substantial additional research on tire rolling resistance for medium- and heavy-duty applications. This research involved direct discussions with tire suppliers, assessment of the comments received, additional review of tire products available, and a more thorough review of tire use in the field.  In addition, EPA has conducted tire rolling resistance testing to help inform the final rulemaking.
The agencies discussed many aspects of low rolling resistance tire technologies and their application to medium- and heavy-duty vehicles with tire suppliers since publication of the NPRM.  Several tire suppliers indicated to the agencies that low rolling resistance tires are currently available for vocational applications that would enable compliance with the proposed vocational vehicle standards, such as delivery vehicles, refuse vehicles, and other vocations.  However, the supplier conversations also made the agencies aware that availability of low rolling resistance tires varies by supplier. Some suppliers stated they focused their company resources on areas of the medium- and heavy-duty vehicle spectrum where fleet operators would see the most fuel efficiency benefits for the application of low rolling resistance technologies; specifically the long-haul, on-highway applications that drive many miles and use large amounts of fuel.  These suppliers stated that this choice was driven by the significant capital investment that would be needed to improve tire rolling resistance across the relatively large number of product offerings in the vocational vehicle segment, based on the wide range of tire sizes, load ratings, and speed ratings, compared to the much narrower range of offerings for long-haul applications.  Other suppliers stated that they have made conscious efforts to reduce the rolling resistance of all of their medium- and heavy-duty vehicle tire offerings, including vocational applications, in an effort to become leaders in this technology.
The agencies also discussed with tire suppliers the potential tire attribute tradeoffs that may be associated with incorporating designs that improve tire rolling resistance, given the driving patterns, environmental conditions, and on-road and off-road surface conditions that vocational vehicles are subjected to.  Some vehicle manufacturer commenters had suggested that changes in tire tread block design that improve rolling resistance may adversely affect tire performance characteristics such as traction, resistance to tearing, and resistance to wear and damage from scrubbing on curbs and frequent tight radius turns that are important to customers for vocational vehicle performance.  The suppliers agreed that providing tires unable to withstand these conditions or meet the vehicle application needs would adversely affect customer satisfaction and warranty expenses, and would have detrimental financial effects to their businesses. One supplier indicated that in some cases, tread-wear (tire life) could be compromised if suppliers choose to reduce the initial tire tread depth without any offsetting tire compound or design enhancements as the means to achieve rolling resistance reductions. That supplier argued that taking this approach could lead to more frequent tire replacements or re-treading of existing tire carcasses, and that the agencies should therefore take a total lifecycle view when evaluating the effects of driving rolling resistance reductions.  That supplier also indicated that a correlation of a 20 percent reduction in rolling resistance achieved through tread depth reduction could lead to a 30 percent decrease in tread-life and 15 percent reduction in wet traction.  The agencies note that when they inquired about potential `safety' related tradeoffs, such as traction (braking and handling) and tread wear when applying low rolling resistance technologies, tire suppliers consistently responded that they would not produce a tire that compromises safety when fitted in its proper application.
In addition to the supplier discussions and evaluation of comments to the Notice of Proposed Rulemaking, EPA conducted a series of tire rolling resistance tests on medium- and heavy-duty vocational vehicle tires.  The testing measured the RRC of tires representing 16 different vehicle applications in Classes 4 - 8.  The testing included approximately 5 samples each of both steer and drive tires for each application. The tests were conducted by two independent tire test labs, Standards Testing Lab (STL) and Smithers-Rapra (Smithers).