into vehicles. (Are the number and variety of secondary tasks in fact
multiplying or does it just seem that way?) Many people have speculated
that making it safer for drivers to perform secondary tasks while
driving will encourage drivers to perform more secondary tasks while
driving. This is another application of risk homeostasis theory; people
have an acceptable level of risk that they are comfortable with and
they compensate for reductions in risk by taking on additional risks so
as to maintain a relatively constant level of risk.
    There is undoubtedly a certain amount of truth to risk homeostasis
theory with regard to driving safety. For example, over the last 50
years, numerous safety improvements have been implemented in motor
vehicles. Risk homeostasis theory predicts that drivers would drive
more dangerously so as to maintain their overall acceptable level of
risk. One way to do this is by driving faster. There is some evidence
that this has happened. Speed limits have been increased. While drivers
used to speed when the national speed limit was 55 mph, they still
speed today when interstate highway speed limits have been increased to
65 to 75 mph. However, there is a clearly decreasing trend in the
number of motor vehicle fatalities, especially when they are normalized
by the number of vehicle miles traveled.
    What seems to have happened in the past is that safety improvements
have been partially, but not totally, offset by riskier driving
behavior (frequently by increases in driving speed). However,
substantial improvement in safety has remained, even after the changes
in driver behavior. True risk homeostasis did not occur, but we did see
behavioral adaptation as drivers partially compensated for the decrease
in risk.
    NHTSA anticipates that similar changes in driver behavior may be
seen due to these NHTSA Guidelines. Some portion of the otherwise
expected improvement in safety and reduction in driver workload
associated with task performance may be used by drivers to perform more
secondary tasks. However, there should also be an improvement in
overall driving safety.
    While NHTSA's primary focus is driving safety, other things are
also important to drivers. Drivers, like any other category of people,
will seek to have their personal needs met. Drivers are not forced to
perform additional secondary tasks just because they have a vehicle
designed for safe in-vehicle secondary task performance. Drivers
perform these additional secondary tasks to meet their own needs. Even
though some portion of the expected improvement in safety may be
negated by the performance of more secondary tasks, the overall quality
of life will be improved for drivers and other road users.

VI. Justification for Specific Portions of NHTSA Guidelines for
Reducing Driver Distraction During Interactions With In-Vehicle Systems

A. Intended Vehicle Types

    These proposed NHTSA Guidelines are appropriate for all passenger
cars, multipurpose passenger vehicles, and trucks and buses with a GVWR
of not more than 10,000 pounds. These are what NHTSA has traditionally
called ``light vehicles.'' This category of vehicles has been the
primary focus of NHTSA's past driver distraction research.
Additionally, light vehicles have been a major platform for the push to
incorporate built-in advanced technology, entertainment, and
communications functions into vehicles. Focusing on this vehicle
category serves as a step towards ensuring that the increasing features
being offered in all vehicles do not produce an overwhelmingly
distracting in-vehicle environment for the driver that can degrade
safety. For these reasons, NHTSA has focused its distraction research
on light vehicles. While much of what NHTSA has learned about light
vehicle driver distraction undoubtedly applies to other vehicle types,
additional research would be needed to assess whether all aspects of
these NHTSA Guidelines are appropriate for application to those vehicle
types.

B. Existing Alliance Guidelines Provide a Starting Point

    The NHTSA Guidelines derive in part from the document ``Statement
of Principles, Criteria, and Verification Procedures on Driver
Interactions with Advanced In-Vehicle Information and Communication
Systems including 2006 Updated Sections'' that was developed by the
Alliance of Automobile Manufacturer's Driver-Focus Working Group
(frequently referred to as the Alliance Guidelines).\61\ Portions of
the Alliance Guidelines have been carried over to the NHTSA Guidelines
without changes. When the NHTSA Guidelines differ from the Alliance
Guidelines, it is either due to recent research that has been performed
since the development

of the Alliance Guidelines or because NHTSA believes that the changes
made will increase the safety of the motoring public.
---------------------------------------------------------------------------

    \61\ Driver Focus-Telematics Working Group, ``Statement of
Principles, Criteria and Verification Procedures on Driver-
Interactions with Advanced In-Vehicle Information and Communication
Systems,'' June 26, 2006 version, Alliance of Automobile
Manufacturers, Washington, DC.
---------------------------------------------------------------------------

    A number of the Alliance Guideline principles are not included in
the NHTSA Guidelines. While NHTSA generally agrees with the excluded
principles, NHTSA thinks that these principles are not appropriate to
include in these NHTSA Guidelines.
    The excluded principles, and their reasons for exclusion, are as
follows:

     Principle 1.1: The system should be located and fitted
in accordance with relevant regulations, standards, and the vehicle
and component manufacturers' instructions for installing the systems
in vehicles.\62\
---------------------------------------------------------------------------

    \62\ P. 13, Driver Focus-Telematics Working Group, ``Statement
of Principles, Criteria and Verification Procedures on Driver-
Interactions with Advanced In-Vehicle Information and Communication
Systems,'' June 26, 2006 version, Alliance of Automobile
Manufacturers, Washington, DC.

    NHTSA assumes that vehicle manufacturers will follow this principle
when deciding where to locate devices within their vehicles. However,
verification by NHTSA that devices meet this principle is difficult.
The Alliance Guidelines verification section for this principle does
---------------------------------------------------------------------------
not offer much guidance; it merely states:

    Design to conform and validate by appropriate means as may be
specified by relevant standards or regulations or manufacturer-
specific instruction.\63\
---------------------------------------------------------------------------

    \63\ Ibid, P. 14.

    As discussed above, NHTSA intends to monitor whether vehicles meet
these NHTSA Guidelines to help determine their effectiveness and
sufficiency. Accordingly, the NHTSA Guidelines do not include
principles for which there is no reasonable method for NHTSA to assess
Guideline adherence. It is hard for NHTSA to do this, at least for some
devices, without having access to information known to the manufacturer
but not necessarily to NHTSA. For these reasons, we do not believe it
is feasible for NHTSA to develop the methods needed to monitor
---------------------------------------------------------------------------
adherence to this principle.

     Principle 1.5: Visual displays should be designed and
installed to reduce or minimize glare and reflections.\64\
---------------------------------------------------------------------------

    \64\ Ibid, P. 37.

    Vehicle manufacturers report that they follow this principle when
installing when deciding where to locate devices within their vehicles.
Additionally, verification by NHTSA that devices meet this principle is
difficult. The Alliance Guidelines verification section for this
---------------------------------------------------------------------------
principle again does not offer much guidance; it merely states:

    Verification should be done by appropriate means (e.g.,
analysis, inspection, demonstration, or test).\65\
---------------------------------------------------------------------------

    \65\ Ibid, P. 37.

    Furthermore, glare and reflections on device interfaces only
indirectly contribute to driver distraction (and thereby affect
safety). Finally, glare and reflection reduction and minimization is a
complex problem that is best left to the vehicle designer. For all of
these reasons, it does not seem feasible for NHTSA at this time to
develop the complicated methods needed to monitor adherence to this
---------------------------------------------------------------------------
principle.

     Principle 5.1: The system should have adequate
instructions for the driver covering proper use and safety-relevant
aspects of installation and maintenance.\66\
---------------------------------------------------------------------------

    \66\ Ibid, P. 79.
---------------------------------------------------------------------------

     Principle 5.2: Safety instructions should be correct
and simple.\67\
---------------------------------------------------------------------------

    \67\ Ibid.
---------------------------------------------------------------------------

     Principle 5.3: System instructions should be in a
language or form designed to be understood by drivers in accordance
with mandated or accepted regional practice.\68\
---------------------------------------------------------------------------

    \68\ Ibid.
---------------------------------------------------------------------------

     Principle 5.4: The instructions should distinguish
clearly between those aspects of the system that are intended for
use by the driver while driving, and those aspects (e.g. specific
functions, menus, etc) that are not intended to be used while
driving.\69\
---------------------------------------------------------------------------

    \69\ Ibid.

    All four of these principles relate to the adequacy of the
instructions that are provided to the driver. NHTSA does not have an
objective means to determine instruction adequacy for a potentially
broad range of device instructions. Therefore, we have excluded these
---------------------------------------------------------------------------
four principles from the NHTSA Guidelines.

     Principle 5.5: Product information should make it clear
if special skills are required to use the system or if the product
is unsuitable for particular users. \70\
---------------------------------------------------------------------------

    \70\ Ibid.
---------------------------------------------------------------------------

     Principle 5.6: Representations of system use (e.g.
descriptions, photographs, and sketches) provided to the customer
with the system should neither create unrealistic expectations on
the part of potential users, nor encourage unsafe or illegal
use.\71\
---------------------------------------------------------------------------

    \71\ Ibid.

    Both of these principles relate to the appropriateness of content
in information about the device provided to the driver by the vehicle
manufacturer. NHTSA does not believe that it is appropriate for NHTSA
to determine the appropriateness of content in information provided to
the driver by the vehicle manufacturer. Therefore, we have excluded
both of these principles from the NHTSA Guidelines.

C. International Harmonization and Voluntary Consensus Standards

    NHTSA is aware of the fact that since vehicles designed in many
countries are sold in the United States and that vehicles designed in
the United States are sold in many countries, motor vehicle
manufacturers' desire internationally harmonized regulations.
Unfortunately, comprehensive, internationally-harmonized, driver
distraction prevention and reduction guidelines do not yet exist.
(Although the high degree of similarity between the Alliance and
European Guidelines is a good start towards international
harmonization, NHTSA would like to see these guidelines made more
stringent so as to better protect the safety of the motoring public.)
Where international and voluntary consensus standards exist that are
useful for portions of the NHTSA Guidelines, they have been carefully
considered and utilized when appropriate. Specifically, for performing
occlusion testing, NHTSA has used International Standards Organization
(ISO) International Standard 16673:2007, ''Road Vehicles--Ergonomic
Aspects of Transport Information and Control Systems--Occlusion Method
to Assess Visual Demand due to the use of In-Vehicle Systems.''
Additionally, NHTSA has used SAE Surface Vehicle Recommended Practice
J941-2010, ``Motor Vehicle Drivers' Eye Locations,'' published March
16, 2010, to determine the driver's eye point when determining the
downward viewing angle to device displays.
    NHTSA hopes that, in the future, it will be possible to develop the
NHTSA Guidelines into an internationally harmonized practice.
    The remainder of this section consists of a detailed discussion and
justification of major items in the NHTSA Guidelines.

D. Statement of General Responsibilities

    New in-vehicle technologies are being developed at an extremely
rapid pace. NHTSA does not have the resources to evaluate the safety
implications of every new device before it is introduced into vehicles.
Such a practice would dramatically slow the rate of introduction of new
technology into vehicles. Finally, and most importantly, adopting such
a practice is unnecessary in light of the National Traffic and Motor
Vehicle Safety Act of 1966's \72\ requirement that each manufacturer
bears primary responsibility for products that they produce that are in

motor vehicles. A manufacturer that produces a vehicle or item of motor
vehicle equipment that either does not comply with the FMVSSs or
contains a defect creating an unreasonable risk to safety must recall
the vehicle or equipment and provide the owner a remedy. 49 U.S.C.
30118-30120.
---------------------------------------------------------------------------

    \72\ 80th Congress, Statute 718.
---------------------------------------------------------------------------

    Accordingly, a section has been included in the NHTSA Guidelines
emphasizing that, to protect the general welfare of the people of the
United States; manufacturers are responsible for refraining from
introducing new in-vehicle devices that create unreasonable risks to
the safety of the driving public.

E. Scope--Devices for Which the NHTSA Guidelines Are Appropriate

    The NHTSA Guidelines are appropriate for all information,
navigation, communications, and entertainment systems integrated into
the vehicle by the vehicle manufacturer. Note that, unlike the Alliance
Guidelines, these NHTSA Guidelines are considered to be appropriate for
both conventional and advanced varieties of information, navigation,
communications, and entertainment systems.
    The NHTSA Guidelines are not appropriate for collision warning or
vehicle control systems. These systems are intended to aid the driver
in controlling the vehicle and avoiding crashes and, therefore, are
justified in capturing the driver's attention. The purpose of collision
warning systems, in particular, is to alert the driver quickly to an
unsafe condition and motivate the driver to make control inputs in an
effort to avoid a crash. The idea of minimizing distraction stemming
from this type of system is in conflict with their purpose--providing
safety warnings to inattentive drivers.
    In addition, other conventional controls and displays such as
heating-ventilation-air conditioning (HVAC), instrument panel gauges
and telltales, etc., are also out-of-scope for the NHTSA Guidelines.
This is because operating vehicle control systems and looking at the
related displays are part of the primary driving task, and are
therefore not considered a distraction. Furthermore, attempting to
include these devices in the scope of these NHTSA Guidelines could
result in conflicts with either current or possible future Federal
Motor Vehicle Safety Standards.

F. Definition of a Task

    NHTSA tasked the Virginia Tech Transportation Institute (VTTI) to
examine the Alliance Guideline's existing definition of a task to
assess whether improvements to the definition could be made. In
addition to reviewing the Alliance Guidelines, VTTI interviewed nine
outside experts from academia, government, and industry about their
use, and possible improvements to, the Alliance Guideline's definition.
    VTTI's interviews found that experts were generally satisfied with
the Alliance Guideline's definition of a task but believed that it
could use some clarifications. Based on their self-reporting, the
experts were generally using the Alliance Guideline's definition of a
task consistently except for differences as to the precise start and
end points of a task. These differences could affect whether a task
meets the acceptance criteria for assessing whether a secondary task
performed using an in-vehicle device may be suitable for performance
while driving, due to its minimal impact on driving performance and,
therefore, safety.
    Additional details regarding this VTTI expert panel effort will be
summarized in a NHTSA report to be released in 2012.
    One VTTI recommendation that has been adopted in the NHTSA
Guidelines is to emphasize that only tasks that can be reasonably
subjected to a test should be subjected to a test, i.e., do not test a
task that is unbounded in duration and do not test a task that has no
measurable magnitude or dose. Therefore, VTTI recommended that NHTSA
refer to tasks in its NHTSA Guidelines as Testable Tasks. These
Testable Tasks have well defined points at which the Start of Data
Collection and End of Data Collection occur, which should resolve the
differences seen between various experts on this issue of task start
and end points.
    Finally, VTTI recommended that NHTSA provide additional explanatory
information and examples about Testable Task definitions. This
information will be provided in a forthcoming NHTSA Technical Report.

G. Definition of Lock Out

    To achieve the purpose of the NHTSA Guidelines, tasks that that do
not meet the guideline criteria (or devices that are inherently
distracting such as full-motion video displays) should be disabled so
that they will not be accessible (i.e., be ``locked out'') to the
driver while ``driving'' a motor vehicle.
    On October 1, 2009, President Obama issued an Executive Order,
``Federal Leadership on Reducing Text Messaging While Driving,'' \73\
that instructed Federal employees and contractors not to perform text
messaging while driving a United States Government owned vehicle, while
driving their personal vehicle on official, United States Government,
business, or while driving and using a United States Government owned
electronic device. The Executive Order defines driving as follows:
---------------------------------------------------------------------------

    \73\ Executive Order, ``Federal Leadership on Reducing Text
Messaging While Driving,'' October 1, 2009, retrieved from http://www.whitehouse.gov/the_press_office/Executive-Order-Federal-Leadership-on-Reducing-Text-Messaging-while-Driving/ on March 22,
2011.

    ``Driving'' means operating a motor vehicle on an active roadway
with the motor running, including while temporarily stationary
because of traffic, a traffic light or stop sign, or otherwise. It
does not include operating a motor vehicle with or without the motor
running when one has pulled over to the side of, or off, an active
roadway and has halted in a location where one can safely remain
stationary.\74\
---------------------------------------------------------------------------

    \74\ The U.S. Department of Transportation's Federal Motor
Carrier Safety Administration (FMCSA) and Pipeline and Hazardous
Materials Safety Administration (PHMSA) use a slightly different
definition of driving. Their definition limits driving to operating
a commercial motor vehicle on a highway. NHTSA is basing its
definition of driving upon the one contained in the Executive Order
because NHTSA is concerned with all vehicles operating on any type
of roadway.

    NHTSA is proposing to make its definition of ``driving'' in the
context of these NHTSA Guidelines consistent with the Executive Order's
definition of ``driving.'' However, because these NHTSA Guidelines are
meant for vehicle manufacturers designing in-vehicle integrated
electronic device interfaces, the agency is proposing a definition that
is framed in terms of the status of the vehicle rather than the conduct
of the driver. Specifically, the NHTSA Guidelines recommend disabling
unreasonably distracting tasks and/or devices while driving. For the
NHTSA Guidelines, ``while driving'' is defined as any time the
vehicle's engine is turned on and its transmission is not in ``Park''
(for automatic transmission vehicles; for manual transmission vehicles
this changes to when the transmission is not in ``Neutral'' or the
parking brake is ``Off'').\75\
---------------------------------------------------------------------------

    \75\ Without the addition of expensive equipment vehicle
manufacturers cannot know when the driver has pulled over to the
side of, or off of, an active roadway and has halted in a location
where the vehicle can safely remain stationary. For automatic
transmission-equipped vehicles, the vehicle manufacturer can
determine the position of the gear shift (this information is
available on the Controller Area Network Bus (CANbus) for all modern
vehicles). So operationally, NHTSA is equating placing the vehicle
in ``park'' with ``the vehicle has halted in a location where the
vehicle can safely remain stationary.'' For manual transmission
vehicles, placing the vehicle in ``park'' is replaced by placing the
vehicle in ``neutral'' with the parking brake on. Again, these are
things that the vehicle manufacturer easily determine (available
from the CANbus) and do not add extra cost.

---------------------------------------------------------------------------

H. Per Se Lock Outs

    The NHTSA Guidelines contain a recommended list of ``per se'' lock
outs for in-vehicle devices tasks that are considered unsafe for
performance by the driver while driving. Per se lock outs are ones
based on either public policy or law. They are meant for in-vehicle
device tasks that are either obviously inappropriate for performance by
a vehicle driver while driving or ones (such as photographic or
graphical moving or still images not related to driving) for which the
task-based test paradigm used to determine the acceptability of a task
for performance while driving will not work due to the task being
unbounded in some aspect.
    After much consideration, NHTSA has decided to propose the
following list of tasks considered to be suitable for lock out on a per
se basis:
     Displaying photographic or graphical moving visual images
not related to driving. This would include things such as video phone
calls and other forms of video communication, as well as pre-recorded
video footage, and television. Images considered to be related to
driving include information that is useful in monitoring vehicle
occupant status, maneuvering the vehicle, or assisting in route
planning. Short, scrolling lists under the control of the driver (e.g.,
navigation system destinations) should not be significantly distracting
provided the information is presented in accordance with these NHTSA
Guidelines. A visual image depicting blind zone areas around the
vehicle would be considered information related to the driving task.
Also, weather information that relates to the vicinity of the car,
intended route information (such as a closed exit), or emergency
information (such as the approach of an emergency response vehicle) are
all considered to be information related to driving.
     Displaying photographic or graphical static visual images
not related to driving. This would include album art and personal
photos, among other things.
     Automatically scrolling text.
     Manual text entry (e.g., drafting text messages, keyboard-
based text entry). The driver should not input more than 6 button or
key presses during the performance of a task. This limit is based on an
assumed driver eyes-off-road time of 2.0 seconds per button or key
press and NHTSA's maximum permitted total eyes-off-road time for a task
of 12.0 seconds.
     Reading more than 30 characters, not including punctuation
marks, of visually presented text (a number, no matter how many digits
it contains, and a units designation (e.g., mpg) each count as only one
character). This character limit is taken from the JAMA Guidelines and
is intended to prevent such tasks as reading text messages, reading
electronic books, and manual Internet browsing. As pointed out by
Transport Canada:

    The JAMA Guidelines are currently the most demanding
recommendations set by the industry internationally.\76\

    \76\ ``Strategies for Reducing Driver Distraction from In-
Vehicle Telematics Devices: A Discussion Document,'' prepared by the
Standards Research and Development Branch of the Road Safety and
Motor Vehicle Regulations Directorate of Transport Canada, TP 14133
E, April 2003.

    NHTSA believes that all of these activities are either obviously
inappropriate for performance by a vehicle driver (e.g., manual text
entry while driving) or ones for which the task-based test paradigm
used to determine lock outs on a task-by-task basis will not work
(e.g., viewing video images not related to driving, viewing static
images not related to driving, and automatically scrolling text) or
both (e.g., reading more than 30 characters of visually presented
text).
    Rearview images presented for the purpose of aiding a driver to
detect obstacles in the vehicle's path during a backing maneuver should
not be locked out when presented in accordance with the allowable
circumstances specified in FMVSS No. 111 since this information is
driving related and for the purposes of improving safety.

I. Steering Wheel-Mounted Control Restrictions

    The NHTSA Guidelines recommend that all device functions accessed
via visual-manual interaction by the driver should be operable by
using, at most, one of the driver's hands in order to be considered
suitable for performance while driving.
    For device controls located on the steering wheel, the Alliance
Guidelines state that no device tasks should require simultaneous
manual inputs from both hands, except in the following condition: one
of the two hands maintains only a single finger input (e.g., analogous
to pressing ``shift'' on a keyboard). After due consideration, NHTSA
has decided that it is not comfortable with this exception. NHTSA is
concerned that tasks that require the simultaneous use of both hands,
even one for which only a single finger input is required from one
hand, will result in an unsafe situation. Therefore, the NHTSA
Guidelines recommend against driver interfaces that utilize this
special case of two-handed control.

J. Maximum Downward Viewing Angle

    The NHTSA Guidelines recommend that the each device's active
display area be located as close as practicable to the driver's forward
line of sight. They include a specific recommendation for the maximum
downward viewing angle to the geometric center of each display.
    To determine a display's downward viewing angle, a nominal driver
eye point must be selected. The NHTSA Guidelines recommend that the
nominal driver eye point be that contained in the March 2010 revision
of SAE Surface Vehicle Recommended Practice J941 ``Motor Vehicle
Drivers' Eye Locations.''
    Each device's display(s) should be mounted in a position where the
downward viewing angle, measured at the geometric center of each active
display area, is less than at least one of the following two angles:
     The 2D Maximum Downward Angle, or
     The 3D Maximum Downward Angle.
    The 2D Maximum Downward Angle is equal to:
     30.00 degrees for a vehicle with the height of the nominal
driver eye point less than or equal to 1700 millimeters above the
ground.
     Given by the following equation for nominal driver eye
point heights greater than 1700 millimeters above the ground:

[GRAPHIC] [TIFF OMITTED] TN24FE12.058

    These recommendations for the maximum display downward viewing
angle are the same as those contained in the Alliance Guidelines except
that the nominal driver eye point is slightly different. The Alliance
Guidelines set the nominal driver eye point at the point specified in
the June 1997 revision of SAE Surface Vehicle Recommended Practice J941
``Motor Vehicle Drivers' Eye Locations.'' The Alliance Guidelines then
add 8.4 mm to the height of the driver's nominal eye point. The
driver's eye point location used by the NHTSA Guidelines is close to
that used by the Alliance Guidelines for typical seat back angles.
Therefore, this change is not expected to have any effects on the
stringency of the NHTSA Guidelines compared to the Alliance Guidelines.
The only reason for making this change is to avoid using an older
version of an SAE standard when a newer version has already been
adopted.

K. Tests Considered To Determine What Tasks Should Be Accessible While
Driving

    During development of the NHTSA Guidelines for visual-manual
interfaces, the Agency considered seven test protocols and sets of
acceptance criteria for determining whether performance of a task while
driving is unreasonably distracting and should be locked out. This
section will discuss the origins of these seven test protocols and sets
of acceptance criteria. The subsequent section will discuss which of
these test protocols and criteria NHTSA prefers for use in determining
whether a task is unreasonably distracting.
    Several of the candidate test protocols and sets of acceptance
criteria were taken from the Alliance Guidelines. The Alliance
Guidelines contain two alternatives for determining whether a task is
unreasonably distracting for drivers while driving. These alternatives
are discussed under Principle 2.1 of the Alliance Guidelines:

    Systems with visual displays should be designed such that the
driver can complete the desired task with sequential glances that
are brief enough not to adversely affect driving.\77\
---------------------------------------------------------------------------

    \77\ Driver Focus-Telematics Working Group, ``Statement of
Principles, Criteria and Verification Procedures on Driver-
Interactions With Advanced In-Vehicle Information and Communication
Systems,'' June 26, 2006 version, Alliance of Automobile
Manufacturers, Washington, DC, P. 38.

---------------------------------------------------------------------------
    The Alliance Guideline's Alternative A reads:

    A visual or visual-manual task intended for use by a driver
while the vehicle is in motion should be designed to the following
criteria:
    A1. Single glance durations generally should not exceed 2
seconds; and
    A2. Task completion should require no more than 20 seconds of
total glance time to display(s) and controls.\78\
---------------------------------------------------------------------------

    \78\ Ibid, P. 39.

    The Alliance Guidelines include the following three verification
procedures for Alternative A:
    1. Eye Tracker Measurement. An eye tracker is used to measure the
number and length of glances to the device while performing a task
while driving either in a driving simulator, on a test track, or on an
actual roadway using a standard driving scenario.
    2. Video Recording of Test Participant's Eyes/Face. Post-testing,
video of the test participant's eyes and face is reviewed and the
number and length of glances to the device while performing a task
while driving either in a driving simulator, on a test track, or on an
actual roadway using a standard driving scenario is determined.

    3. Occlusion Testing. Test participants perform the secondary task
(but not the driving task) while undergoing alternating periods of time
when they can and cannot see. The periods of time when they can and
cannot see are generated either by occlusion goggles or some other
means such as an opaque shutter that is placed and removed periodically
from in front of the test participants' eyes. When performing occlusion
testing, the Alliance Guidelines reduce the maximum permitted single
glance durations to 1.5 seconds (forced by the occlusion cycle time)
and the maximum permitted total glance time to 15 seconds. Note that
the Alliance Guidelines occlusion testing technique uses a different
occlusion cycle time (1.5 seconds open/1.0 second closed) than that
called for by ISO International Standard 16673:2007, ``Road Vehicles--
Ergonomic Aspects of Transport Information and Control Systems--
Occlusion Method To Assess Visual Demand due to the use of In-Vehicle
Systems'' (1.5 seconds open/1.5 seconds closed).
    In developing these Guidelines, NHTSA considered the Alliance
Principle 2.1 Alternative A techniques for determining whether a task
is unreasonably distracting to be performed by drivers while driving.
For test participant and other road user safety reasons, NHTSA has
decided to recommend that NHTSA Guideline testing for the purposes of
determining whether a task is suitable for performance while driving
should not be performed on either test tracks or public roadways.
NHTSA's fear is that, if such testing were performed on either test
tracks or public roadways, it might be discovered that a task is
unreasonably distracting by having a crash occur. Therefore, the NHTSA
Guidelines suggest limiting testing to that performed in driving
simulators, vehicle mockups, or similar, non-dangerous, testing venues.
    NHTSA considered three test protocols and sets of acceptance
criteria for determining whether a task is too distracting to be
performed by drivers while driving that were based on Alliance
Principle 2.1 Alternative A. For the purposes of this notice, Alliance
Alternative A Verification Option 1, Eye Tracker Measurement, and
Verification Option 2, Video Recording of Test Participant's Eyes/Face
were considered together by NHTSA as Option EGDS: Eye Glance Testing
Using a Driving Simulator. Alliance Alternative A Verification Option
3, Testing using Occlusion, was considered by NHTSA as Option OCC:
Occlusion Testing. Additionally, NHTSA considered a third verification
option that is a variant of the Alliance Alternative A techniques,
Option STEP: Step Counting.
    The idea behind Option STEP: Step Counting is to first perform a
detailed task analysis of the task under consideration on the device
being studied. After the detailed task analysis has decomposed the task
into elemental components, a number of ``steps'' are assigned to each
elemental component. Tasks that require more than a set number of steps
are considered to be too distracting to be performed by drivers while
driving.
    The Alliance Guideline's Alternative B reads:

    Alternatively, the impact of a device-related visual or visual-
manual task on driving safety can be assessed directly by measuring
concurrent driving performance under dynamic conditions and relating
it to driving performance under specified reference conditions. The
influence of such a secondary task shall not be greater than that of
a scientifically-accepted reference task in terms of:
    B1. Lateral position control: Number of lane exceedances
observed during secondary task execution should not be higher than
the number of lane exceedances observed while performing one or more
reference tasks (e.g., manual radio tuning) under standard test
conditions (e.g., same drivers, driving scenario) replicating
routine driving tasks; and
    B2. Following headway: Car following headway variability
observed during secondary task execution should not be worse than
car following headway observed while performing one or more
reference tasks under standard test conditions (e.g., same drivers,
same driving scenario) replicating routine driving tasks. This
measure is influenced by speed changes of preceding traffic or lane
changes of other vehicles.\79\
---------------------------------------------------------------------------

    \79\ Ibid, p. 39.

    For Alliance Principle 2.1 Alternative B, the recommended Alliance
reference task is radio tuning. This task (which will be referred to as
manual radio tuning) does not use a preset button to switch to a
desired radio station. Manual radio tuning consists of first toggling
betweens bands (AM to FM or vice versa) and then using the tuning
controls to select a station at a specified frequency.
    Alliance Principle 2.1 Alternative B consists of performing a task
while driving either in a driving simulator, on the test track, or on
an actual roadway using a standard driving scenario. However, for
previously discussed reasons of safety, the NHTSA Guidelines research
limit testing for this alternative to driving simulators.
    NHTSA considered two test protocols and sets of acceptance criteria
for determining whether a task is too distracting to be performed by
drivers while driving that were based on Alliance Alternative B. These
were Option DS-BM: Driving Test Protocol with Benchmark and Option DS-
FC: Driving Test Protocol with Fixed Acceptance Criteria. Option DS-BM
is based on the test protocols used by Alliance member companies when
performing Alternative B testing and uses, as its name implies, radio
tuning as its reference task.
    One concern with Alliance's implementation of the radio tuning
reference task is that it is insufficiently specific to prevent
designers from developing radios that are more difficult for drivers to
tune. While the Alliance has told NHTSA that they intended the
reference radio to be representative of a 1980's production radio, the
Guideline text lacks the detail needed to ensure a fixed-difficulty
reference task. As a result, some designers may interpret the Alliance
Guidelines to permit more complicated radios to be used, thereby
increasing the difficulty of the reference task and allowing more
complex secondary tasks to meet the benchmark acceptance criteria. To
better achieve the goal of a fixed-difficulty reference task, NHTSA
considered a similar option that instead uses fixed driving performance
values for lane exceedances and headway variability. This testing
option is called Option DS-FC: Driving Test Protocol with Fixed
Acceptance Criteria.
    Over the past few years, NHTSA has worked independently on the
development of a test protocol and acceptance criteria for determining
whether a secondary task is too distracting for drivers to perform
while driving. This research is documented in a recently released NHTSA
technical report.\80\ The test protocol combines eye glance metrics
similar to those of Alliance Alternative A, driving performance
variability metrics similar to those of Alliance Alternative B, and
target detection metrics to attain a comprehensive protocol that NHTSA
believes is useable for both visual-manual and auditory-vocal driver
interfaces.
---------------------------------------------------------------------------

    \80\ Ranney, T.A., Baldwin, G.H.S., Parmer, E., Domeyer, J.,
Martin, J., and Mazzae, E. N., ``Developing a Test to Measure
Distraction Potential of In-Vehicle Information System Tasks in
Production Vehicles,'' DOT HS 811 463, November 2011.
---------------------------------------------------------------------------

    In developing this protocol, NHTSA considered two existing test
protocols and sets of acceptance criteria for determining whether a
task is too distracting to be performed by drivers while driving that
were based upon its

research. These were Option DFD-BM: Dynamic Following and Detection
Protocol with Benchmark and Option DFD-FC: Dynamic Following and
Detection Protocol with Fixed Acceptance Criteria. Option DFD-BM uses
route navigation system destination entry (entry of the full address
including house number, street name, and city name) as a reference
task. Unlike Option DS-BM, where the acceptance criteria are that the
appropriate metric values should not be worse than radio tuning, for
Option DFD-BM the acceptance criteria are that the appropriate metric
values should be better than those associated with the destination
entry reference task.
    The use of a destination entry reference task gives NHTSA similar
concerns as were noted for the radio tuning reference task. If a very
detailed navigation system interface is not specified in the
guidelines, the opportunity may be left for designers to create route
navigation systems for which the destination entry task is more
difficult. The result would be a non-fixed reference task that could be
used to justify more complex secondary tasks as being suitable for
performance while driving. To alleviate this concern, NHTSA also
considered Option DFD-FC: Dynamic Following and Detection Protocol with
Fixed Acceptance Criteria. Option DFD-FC is very similar to Option DFD-
BM except that instead of using a reference task to determine
acceptance, under Option DFD-BM fixed values for the metrics would be
used.
    Table 3 summarizes the seven test protocols and sets of acceptance
criteria for determining whether a task is unreasonably distracting and
should be locked out while driving.

           Table 3--Summary of Distraction Test Protocols and Acceptance Criteria Considered by NHTSA
----------------------------------------------------------------------------------------------------------------
     Option letter            Test name         Performance measures   Acceptance criteria      Testing venue
----------------------------------------------------------------------------------------------------------------
EGDS..................  Eye Glance Testing      Duration of    85% of       Driving Simulator.
                         Using a Driving        individual eye         individual glance
                         Simulator.             glances away from      durations less than
                                                forward road view.     2.0 seconds.
                                                                       Mean of
                                                                       individual glance
                                                                       durations less than
                                                                       2.0 seconds.
                                                                       Sum of
                                                                       individual eye
                                                                       glance durations
                                                                       less than or equal
                                                                       to 12.0.
                                                Sum of
                                                individual eye
                                                glance durations
                                                away from forward
                                                road view.
OCC...................  Occlusion Testing....   Sum of         Sum of       Occlusion.
                                                shutter open times.    shutter open times
                                                                       less than 9.0
                                                                       seconds.
STEP..................  Step Counting........   Number of      Less than 6  Task Analysis.
                                                steps required for     steps required for
                                                task.                  task.
DS-BM.................  Driving Test Protocol   Standard       Performance  Driving Simulator.
                         with Benchmark.        deviation of headway.  measures not
                                                Lane           greater than
                                                exceedances.           benchmark values.
DS-FC.................  Driving Test Protocol   Same as        Performance  Driving Simulator.
                         with Fixed             Option DS-BM.          measures not
                         Acceptance Criteria.                          greater than
                                                                       specified values.
DFD-BM................  Dynamic Following and   Duration of    Option EGDS  Driving Simulator.
                         Detection Protocol     individual eye         eye glance
                         with Benchmark.        glances away from      acceptance criteria
                                                forward road view.     plus.
                                                Sum of         Performance
                                                individual eye         measures less than
                                                glance durations       benchmark values..
                                                away from forward
                                                road view..
                                                Standard
                                                deviation of lane
                                                position.
                                                Car
                                                following delay.
                                                Percent of
                                                visual targets
                                                detected.
                                                Visual
                                                detection response
                                                time.
DFD-FC................  Dynamic Following and   Same as        Option EGDS  Driving Simulator.
                         Detection Protocol     Option DFD-BM          eye glance
                         with Fixed                                    acceptance criteria
                         Acceptance Criteria.                          plus.
                                                                       Performance
                                                                       measures less than
                                                                       specified values.
----------------------------------------------------------------------------------------------------------------

L. NHTSA's Preferred Tests for Determining What Tasks Should Be
Accessible While Driving

    NHTSA has thoroughly evaluated all seven of the candidate test
protocols and acceptance criteria for determining what tasks should be
accessible while driving listed in Table 3. The evaluation criteria
used included:
     Test protocol discriminatory capability,
     Difficulty of performing test protocol, and
     Repeatability of test protocol.
    NHTSA is not, at this time, removing any of the test protocols and
acceptance criteria that are listed in Table 3 from consideration for
use as a task acceptability test protocol(s) in the NHTSA Guidelines.
However, the Agency is indicating that it prefers two of the Table 3
test protocols and that one, or both, of these test protocols are more
likely to be selected. Following due consideration of comments received
in response to this notice, NHTSA will select the test protocols and
acceptance criteria for determining what visual-manual tasks should be
accessible while driving.
    NHTSA has decided that it prefers the following two test protocols
and their associated acceptance criteria:
     Option EGDS: Eye Glance Testing Using a Driving Simulator,
and
     Option OCC: Occlusion Testing.

The Agency's reasons for choosing these two options as its preferred
test protocols and acceptance criteria are

discussed in the remainder of this subsection.
    Two of the test protocols and acceptance criteria that NHTSA
considered, Option DS-BM: Driving Test Protocol with Benchmark and
Option DFD-BM: Dynamic Following and Detection Protocol with Benchmark,
include benchmark tasks. For Option DS-BM, the benchmark task is manual
radio tuning while the benchmark task for Option DFD-BM is entering an
address into a route navigation system.
    The goal of using a benchmark task is to increase the
discriminatory power of a test protocol by comparing the performance of
test participants performing a task using a device against that for the
benchmark task. Both theoretically, and in NHTSA's experimental
testing, the use of a benchmark task reduces the impact of individual
test participant differences on the outcome of testing.
    However, NHTSA has decided that the drawbacks of using a benchmark
task outweigh the advantages. The main drawbacks regarding the use of a
benchmark task are:
     The determination as to what tasks may be performed by the
driver while driving depends not just on the task and the device under
consideration but also on the design of the device with which the
reference task is performed. The level of detail of the benchmark task
specification will affect the repeatability of test results. For
example, if a reference task of manual radio tuning was specified with
minimal radio interface specifications, then performing a task with a
device might be deemed unsuitable for performance while driving in a
vehicle that had a very easy to tune radio but suitable for performance
while driving in a second vehicle that had a more difficult to tune
radio. Testing recently performed for NHTSA by VTTI has found large
vehicle-to-vehicle differences in driver performance during manual
radio tuning so NHTSA knows that this concern is real and not just
hypothetical.
     Not all vehicles have a suitable device for performing the
benchmark task. While virtually all production vehicles have radios
suitable for performing the manual radio tuning task, the Alliance
Guidelines did consider it necessary to include specifications for
simulating a built-in radio to bound the difficulty of the benchmark
task. Many production vehicles do not have a built-in route navigation
system. Again, specifications could be developed for simulating a
built-in route navigation system. However, simulating the device used
for the reference task increases testing complexity and cost while
reducing the meaningfulness of a test.
    Based upon its evaluation, NHTSA believes that two eye glance-
related test protocols and acceptance criteria, Option EGDS: Eye Glance
Testing Using a Driving Simulator, and Option OCC: Occlusion Testing,
are both acceptable methods for determining which tasks should have
lock outs during driving.
    The eye glance-related test protocols have a number of advantages.
These include:
     A clear relationship between eye glance-related metrics
and driving safety exists. A driver's vigilant monitoring of the road
and nearby vehicles is essential to safe driving.
     A substantial research base exists that verifies the
correctness of the above statement and provides quantitative support
for it. Based on analyses of past naturalistic data, we know that
looking away from the forward roadway for up to 2.0 seconds has no
statistically significant effect on the risk of a crash or near-crash
event occurring. However, eyes-off-road times of greater than 2.0
seconds have been shown to increase risk at a statistically significant
level. The risk of a crash or near-crash event increases rapidly as
eyes-off-road time increases above 2.0 seconds.\81\
---------------------------------------------------------------------------

    \81\ Klauer, S.G., Dingus, T.A., Neale, V.L., Sudweeks, J.D.,
and Ramsey, D.J., ``The Impact of Driver Inattention on Near-Crash/
Crash Risk: An Analysis Using the 100-Car Naturalistic Driving Study
Data,'' DOT HS 810 594, April 2006.
---------------------------------------------------------------------------

     An obvious relationship between visual-manual distraction
and eye glance measures exists. Visual-manual distraction strongly
implies that the driver is looking away from the forward road scene.
     Eyes-off-road time is measureable. While not easy to
measure, researchers have been working for more than 30 years to
develop better techniques for measuring driver eyes-off-road times. A
large amount of effort has focused on such topics as the best ways to
ensure coding reliability when reducing eye glance video and the
development of automated eye trackers.
     Commercially available occlusion goggles allow occlusion
testing to be performed without having to develop new hardware.
     ISO standards exist for both eye glance measurement (ISO
15007-1 and ISO 15007-2) and occlusion testing (ISO 16673). This allows
us to take advantage of years of test development effort by the
research community.
    While both of these test protocols have some drawbacks, NHTSA
generally considers these issues to be relatively minor.
    Option EGDS: Eye Glance Testing Using a Driving Simulator suffers
from two problems:
     The need for a driving simulator in which to perform
testing. A driving simulator is an expensive piece of test equipment
that typically requires special, highly trained staff to operate
correctly. The driving simulator should be configured to model the
dynamics of the vehicle being tested. Option EGDS is not alone in
having this problem; Options DS-BM, DS-FC, DFD-BM, and DFD-FC also
require a driving simulator.
     Difficulty in accurately measuring eye glance behavior
from data collected during testing. There are two main methods for
determining eye glance characteristics from test data: through the use
of an eye tracker and by manually extracting eye glance locations and
durations from video recorded data. There are substantial operational
problems associated with both of these methods. For example, using an
eye tracker requires extensive calibration for each test participant,
which substantially adds to the time and expense of testing. Manually
reducing video recorded data to obtain eye glance characteristics is
highly labor intensive, time consuming, and expensive. While both
methods can be used to determine the angle at which a participant's
head is aimed with respect to center, identifying the particular point
of gaze (i.e., where the eyes are pointed, or eye glance location) is
challenging. Both methods of measuring eye glance behavior are even
more difficult for test participants who wear eye glasses, such that
participants who require them to drive are at times avoided,
substantially reducing the test participant pool (in NHTSA's
experience, this is particularly a problem when trying to recruit older
test participants).
    Option OCC: Occlusion Testing avoids both of the drawbacks that are
present for Option EGDS: Eye Glance Testing Using a Driving Simulator.
Testing does not have to be performed in a driving simulator so the
driving simulator related issues are avoided. The occlusion apparatus
constrains when driver eye glances to the task device occur, so the eye
glance analysis difficulties present for Option EGDS are not present
for Option OCC.
    NHTSA's proposed occlusion testing uses a field factor of 75
percent to relate shutter open time during occlusion testing to eyes-
off-road time measured during driving simulator testing. The Alliance
Guidelines and ISO International Standard 16673:2007(E), ``Road
Vehicles--Ergonomic Aspects of Transport Information and Control

Systems--Occlusion Method to Assess Visual Demand due to the use of In-
Vehicle Systems'' also uses this 75 percent field factor. The JAMA
Guidelines, however, use a field factor of 93.75 percent.
    The theoretical rationale of a field factor is that every time a
driver looks away from the forward roadway (for occlusion testing, each
such eye glance is assumed to be 2.0-seconds long), the first 0.50
seconds is spent transitioning the driver's eyes from the roadway to
the object being looked at (i.e., a saccade). As a result, only 1.5-
seconds of a 2.0-second eye glance are available for actually looking
at and manipulating the device interface. Therefore, occlusion testing
is performed in 1.5-second shutter open time periods each corresponding
to one 2.0-second eye glance focused away from the forward roadway.
    NHTSA performed a small study to experimentally determine the most
appropriate field factor.\82\ NHTSA's testing produced a field factor
of 78 percent for occlusion testing that was quite close to the field
factor of 75 percent in the ISO Standard 16673. Since the NHTSA
Guidelines occlusion test procedure is based on the ISO Standard 16673,
the theoretical field factor of 75 percent is used instead of the
experimentally determined field factor of 78 percent throughout the
remainder of this document. Note that the use of the theoretical field
factor is slightly conservative in the sense that it results in shorter
viewing intervals; using the experimentally determined field factor
would increase the viewing intervals from 1.50 seconds to 1.56 seconds.
---------------------------------------------------------------------------

    \82\ Ranney, T.A., Baldwin, G.H.S., Parmer, E., Domeyer, J.,
Martin, J., and Mazzae, E.N., ``Developing a Test to Measure
Distraction Potential of In-Vehicle Information System Tasks in
Production Vehicles,'' DOT HS 811 463, November 2011.
---------------------------------------------------------------------------

    However, Option OCC has one major drawback of its own. Option OCC
does not really test for adherence to the criterion that single glance
durations generally should not exceed 2.0 seconds. The use of an
occlusion apparatus forcibly restricts single glance durations to be no
more than 1.5 seconds long (which, with the 75 percent field factor
being applied to occlusion testing, equates to a 2.0 second eye
glance). If a test participant can complete a task using the occlusion
protocol, it has been demonstrated that drivers can complete the task
with sub-2.0 second eye glance durations. However, just because drivers
can accomplish a task with sub-2.0 second eye glances does not mean
that they actually will limit themselves to sub-2.0 second eye glance
durations when not constrained by occlusion apparatus. Option OCC does
not include any mechanism for ensuring that, during actual driving,
drivers will limit themselves to sub-2.0 second eye glance durations
while performing a given task.
    Option STEP: Step Counting has a major advantage over all of the
other test protocols and acceptance criteria considered by NHTSA in
that it does not require human testing to determine whether a task is
suitable for performing while driving. The task analysis that is
performed for this method should be quite objective since it is
generally quite clear how many button presses or other manual
operations have to be performed in order to perform a task. The
objectivity of Option STEP would be helpful if, at some future time,
NHTSA decided to convert its NHTSA Guidelines into a Federal Motor
Vehicle Safety Standard.
    Since no human performance testing is actually performed, Option
STEP also avoids both of the drawbacks that are present for Option
EGDS: Eye Glance Testing Using a Driving Simulator.
    While not having human performance testing gives Option STEP some
major advantages, it is also the source of this option's major
drawback. Option STEP is based on data using past and present vehicle
designs about the eyes-off-road time required for drivers to perform
common manual actions, such as button presses. However, there are no
guarantees that the eyes-off-road time required to perform these
actions will remain the same for future devices and in-vehicle tasks.
NHTSA does not want to determine that tasks performed on future devices
are safe to perform while driving without performing any human
performance testing.
    Another issue with Option STEP is determining exactly what
constitutes a step in all situations. While it is fairly clear what a
step is for pressing buttons, it is not clear for driver operation of
such interface items as knobs or joysticks.
    Based on recent NHTSA testing, the two test protocols and
acceptance criteria that NHTSA considered which were based on just
driving performance, Option DS-BM: Driving Test Protocol with Benchmark
and Option DS-FC: Driving Test Protocol with Fixed Acceptance Criteria,
both suffer from low statistical power when performed using an
economically reasonable number of test participants. When testing of a
task/device was performed using just 20 test participants, there were
almost no statistically significant differences in driver performance,
even between tasks that were found to be different by other testing
protocols. In order to obtain the power necessary to provide the
discriminatory capability needed to determine which tasks should
require lock outs during driving, many more (on the order of 100) test
participants would need to be tested. This would make this test
protocol impractically time consuming and expensive to perform for the
large number of tasks that will need to be screened.
    One of the reasons for the low discriminatory capability of the
Options DS-BM and DS-FC test protocols and acceptance criteria was due
to their use of lane exceedances as a measure of test participant
performance. Lane exceedances have the advantage of being a measure of
driving performance that appears to generally relate directly to
safety.\83\ However, lane exceedances are low frequency events,
particularly during straight line driving. Secondary tasks can be
performed with no lane exceedances. The relative rarity of lane
exceedances means that a large amount of testing has to be performed to
obtain a statistically stable number of these events.
---------------------------------------------------------------------------

    \83\ Research has indicated that one type of lane exceedance,
specifically those due to ``curve cutting,'' have no relationship to
safety.
---------------------------------------------------------------------------

    One possible alternative to using lane exceedances as a measure of
test participant performance is to use the mean standard deviation of
lane position during task performance as a substitute measure of test
participant performance. This approach was used by the Dynamic
Following and Detection Test Protocol to increase the statistical power
of that test procedure.
    The remaining two test protocols and acceptance criteria that NHTSA
considered, Option DFD-BM: Dynamic Following and Detection Protocol
with Benchmark and Option DFD-FC: Dynamic Following and Detection
Protocol with Fixed Acceptance Criteria, were both based on the Dynamic
Following and Detection (DFD) Test Protocol. This is a test protocol
that has been developed by NHTSA\84\ over the last few years in an
attempt to combine the Alliance Guidelines' test protocols and
acceptance criteria with the Peripheral Detection Task (PDT). This test
protocol is a driving simulator based test protocol. Unlike the other
test protocols evaluated, DFD results are based on a test participant
performing

the same task repeatedly for a 2.5-minute interval. The DFD also uses a
complex lead vehicle speed profile that the test participant is
supposed to follow as well as they can with a fixed headway. It has
acceptance criteria based upon eye glance characteristics, measures of
test participant driving performance, and test participant performance
in performing the PDT concurrently with other secondary tasks.
---------------------------------------------------------------------------

    \84\ Ranney, T.A., Baldwin, G.H.S., Parmer, E., Domeyer, J.,
Martin, J., and Mazzae, E.N., ``Developing a Test to Measure
Distraction Potential of In-Vehicle Information System Tasks in
Production Vehicles,'' DOT HS 811 463, November 2011.
---------------------------------------------------------------------------

    Testing performed by NHTSA\85\ has demonstrated that the DFD test
protocol generally works well for determining whether a task is overly
distracting and should be locked out while driving. Unfortunately,
adding additional measures of test participant performance and
additional acceptance criteria increase test procedure and data
analysis complexity. While this increased analysis complexity may well
be necessary when evaluating a device's auditory-vocal task
interactions, it appears to be unnecessary when evaluating visual-
manual device interfaces. A test protocol and acceptance criteria based
only on eye glance characteristics appears to be adequate for visual-
manual secondary tasks.
---------------------------------------------------------------------------

    \85\ Ibid.
---------------------------------------------------------------------------

    In summary, all of the candidate test protocols and acceptance
criteria that NHTSA evaluated have both advantages and drawbacks.
Therefore, NHTSA is not, at this time, removing any of the test
protocols and acceptance criteria from consideration for being the test
protocol(s) finally selected. However, NHTSA has concluded that the
following two test protocols and associated criteria might be best
suited for the visual-manual NHTSA Guidelines:
     Option EGDS: Eye Glance Testing Using a Driving Simulator,
and
     Option OCC: Occlusion Testing.
    Therefore, a detailed discussion of the basis for the proposed
acceptance criteria will be given only for these two testing options.

M. Eye Glance Acceptance Criteria

    The proposed acceptance criteria for Option EGDS: Eye Glance
Testing Using a Driving Simulator are:
     For at least 21 of the 24 test participants, no more than
15 percent (rounded up) of the total number of eye glances away from
the forward road scene should have durations of greater than 2.0
seconds while performing the secondary task, and
     For at least 21 of the 24 test participants, the mean
duration of all eye glances away from the forward road scene should be
less than 2.0 seconds while performing the secondary task, and
     For at least 21 of the 24 test participants, the sum of
the durations of each individual participant's eye glances away from
the forward road scene should be less than, or equal to, 12.0 seconds
while performing the secondary task one time.
    The rationale for the above acceptance criteria is discussed in the
remainder of this subsection. First, NHTSA's reasons for choosing
manual radio tuning as its reference task are explained. It is from the
manual radio tuning reference task that NHTSA's acceptance criteria
were developed. Next, this document will discuss the Alliance
Guidelines' task acceptance criteria. Then, recent NHTSA research on
driver distraction and performance during manual radio tuning is
presented. Finally, results from the recent NHTSA research on manual
radio tuning are used to develop acceptance criteria.
i. Selection of Manual Radio Tuning as the Reference Task
    The above proposed acceptance criteria were developed based on the
idea of a ``reference'' task. A reference task strategy is used because
no general consensus exists as to the threshold at which an absolute
level of distraction due to a driver performing a task becomes
unacceptably high. However, methods for measuring distraction while
performing a secondary task have been developed. Since there is no
agreed upon absolute level at which distraction becomes unacceptably
high, a relative limit can be developed by comparing the distraction
level associated with a driver performing an ``acceptable'' reference
task with the distraction level associated with a driver performing new
tasks.
    A reference task should be a commonly performed task that is
societally acceptable for drivers to perform while driving. The idea is
that any task that is more distracting than the selected reference task
should be locked out while driving. Tasks that create less distraction
than the selected reference task are suitable for the driver to perform
while the vehicle is in motion.
    NHTSA has chosen traditional, manual radio tuning as its
recommended reference task. Manual radio tuning consists of first \86\
toggling betweens frequency bands (AM to FM or vice versa) and then
using the tuning controls (e.g., rotary knob or continuously-held push
button) to select a station at a specified frequency. The prescribed
manual radio tuning task does not use a preset button to tune to a
desired radio station, which would be considered ``automatic'' radio
tuning.
---------------------------------------------------------------------------

    \86\ In some cases, the first step is to switch to the radio
function, or powering on the device.
---------------------------------------------------------------------------

    The Alliance Guidelines also use manual radio tuning as their
reference task. The Alliance's rationale \87\ for radio tuning as the
reference task is that traditional, manual radio tuning:
---------------------------------------------------------------------------

    \87\ P. 40, Driver Focus-Telematics Working Group, ``Statement
of Principles, Criteria and Verification Procedures on Driver-
Interactions with Advanced In-Vehicle Information and Communication
Systems,'' June 26, 2006 version, Alliance of Automobile
Manufacturers, Washington, DC.
---------------------------------------------------------------------------

     Is a distraction source that exists in the crash record
88 89 and so has established safety-relevance;
---------------------------------------------------------------------------

    \88\ Wang, J.S., Knipling, R.R., and Goodman, M.J., ``The Role
of Driver Inattention in Crashes: New Statistics from the 1995
Crashworthiness Data System,'' 40th Annual proceedings, Association
for the Advancement of Automotive Medicine, Vancouver, British
Columbia, Canada, October 1996.
    \89\ Singh, S., ``Distracted Driving and Driver, Roadway, and
Environmental Factors,'' DOT HS 811 380, September 2010.
---------------------------------------------------------------------------

     Is a typical in-vehicle task that average drivers perform;
     Involves use of an in-vehicle device that has been present
in motor vehicles for more than 80 years;
     Is an in-vehicle device task that is typical in terms of
technological complexity, as well as in terms of impacts on driver
performance; and
     Represents a plausible benchmark for driver distraction
potential beyond which new devices, functions, and features should not
go.
    Vehicle radios/stereos have long been the most common original
equipment system with functionality not directly related to driving.
Driving a car with the radio on is an extremely common and widely
accepted scenario for Americans. Given this fact, it seems reasonable
to allow other tasks to be performed that require a similar degree of
driver interaction and to discourage tasks that are more distracting
than that level.
    The specific reference task of manual radio tuning as defined by
the Alliance involves a defined traditional radio design and two input
steps: a single button press followed by a longer knob turn or button
hold. Many of the most basic and common in-vehicle control inputs a
driver may make require only a single, short duration input (e.g., turn
on headlights, activate turn signal, adjust temperature). Considering
this, manual radio tuning could be considered a worst case traditional
task.
    In recent years, multi-function in-vehicle information systems such
as BMW's iDrive, Ford's SYNC, and several others have come available.

These multi-function systems provide the driver with more than just
music and can involve more complex inputs and/or more steps for the
driver to accomplish tasks. Comparing newer, more complex tasks to the
historical standard of worst-case non-driving tasks allows a
perspective on relative safety to be ascertained.
    Past research efforts have identified crashes that are believed to
be caused by driver distraction due to vehicle radio use. A 1996 study
by Wang, Knipling, and Goodman \90\ analyzed data collected during 1995
by NASS-CDS. This analysis found that distraction due to driver radio,
cassette player, or CD player usage was present in 2.1 percent of all
crashes. There were also 2.6 percent of crashes for which the source of
distraction was unknown. Distributing crashes with an unknown source of
distraction proportionately among the other identified sources of
distraction, the percentage of crashes with distraction due to driver
radio, cassette player, or CD player usage increases to 2.6 percent.
---------------------------------------------------------------------------

    \90\ Wang, J.S., Knipling, R.R., and Goodman, M.J., ``The Role
of Driver Inattention in Crashes: New Statistics from the 1995
Crashworthiness Data System,'' 40th Annual proceedings, Association
for the Advancement of Automotive Medicine, Vancouver, British
Columbia, Canada, October 1996.
---------------------------------------------------------------------------

    A more recent study by Singh \91\ analyzed data from NHTSA's
National Motor Vehicle Crash Causation Survey (NMVCCS) to estimate the
incidence of crashes due to radios and CD players (cassette players in
vehicles are a disappearing technology). This analysis found that
distraction due to driver radio or CD player usage was present in 1.2
percent of all crashes.
---------------------------------------------------------------------------

    \91\ P. 5, Singh, S., ``Distracted Driving and Driver, Roadway,
and Environmental Factors,'' DOT HS 811 380, September 2010.
---------------------------------------------------------------------------

    NMVCCS is NHTSA's most recent, nationally representative, detailed
survey of the causes of light motor vehicle crashes (essentially an
updated version of the Indiana Tri-Level Study of the Causes of Traffic
Accidents \92\ that was conducted in the 1970s). For NMVCCS driver
(including distraction- and inattention-related information), vehicle,
and environment data were collected during a three-year period (January
2005 to December 2007). A total of 6,949 crashes met the specified
criteria for inclusion in NMVCCS. Due to specific requirements that
must be met by crashes for inclusion in NMVCCS, the NMVCCS data differs
from other crash databases such as NASS-CDS or NASS-GES.
---------------------------------------------------------------------------

    \92\ Treat, J.R., Tumbas, N.S., McDonald, S.T., Shinar, D.,
Hume, R.D., Mayer, R.E., Stansifer, T.L., and Castellan, N.J.,
``Tri-Level Study of the Causes of Traffic Accidents: Final Report.
Executive Summary,'' DOT HS 805 099, May 1979.
---------------------------------------------------------------------------

    Unfortunately, there is no way to determine with the data currently
available to NHTSA (i.e., Singh, \93\ Wang, Knipling, and Goodman \94\)
the fraction of the observed crashes due solely to radio usage (or due
to radio tuning specifically).
---------------------------------------------------------------------------

    \93\ Singh, S., ``Distracted Driving and Driver, Roadway, and
Environmental Factors,'' DOT HS 811 380, September 2010.
    \94\ Wang, J.S., Knipling, R.R., and Goodman, M.J., ``The Role
of Driver Inattention in Crashes: New Statistics from the 1995
Crashworthiness Data System,'' 40th Annual proceedings, Association
for the Advancement of Automotive Medicine, Vancouver, British
Columbia, Canada, October 1996.
---------------------------------------------------------------------------

    Making the further assumption that fatality, injury, and property
damage only crashes all have the same percentage of distraction due to
driver radio, cassette player, or CD player usage gives the estimates
shown in Table 4.

 Table 4--Estimated Number of Fatalities, Injuries, and Property Damage
      Only Crashes in 2009 Due to Radio, Cassette, or CD Player Use
------------------------------------------------------------------------
                                                                Wang,
                                                              Knipling,
                                                    Singh        and
                                                   estimate    Goodman
                                                               estimate
------------------------------------------------------------------------
Percentage......................................       1.2%         2.6%
Fatalities......................................        406          869
Injuries........................................     27,000       57,000
Property Damage Only............................     66,000      142,000
------------------------------------------------------------------------

    As stated above, NHTSA accepts the use of manual radio tuning as a
reference task for indicating a driver distraction magnitude beyond
which new devices, functions, features, and tasks should not exceed.
NHTSA agrees with the Alliance rationale for using manual radio tuning
as the reference task and considers it suitable for use as a standard
to which new in-vehicle tasks may be compared.
ii. The Alliance Guidelines Acceptance Criteria
    The Alliance Guidelines include three verification options for
their Alternative A: Eye Tracker Measurement, Video Recording of Test
Participant's Eyes/Face, and Testing using Occlusion. Two of these
verification options, Eye Tracker Measurement and Video Recording of
Test Participant's Eyes/Face, require the determination of test
participant eye glances. Both of these verification options are covered
by NHTSA Option EGDS: Eye Glance Testing Using a Driving Simulator. The
third Alliance Guidelines verification option, Testing using Occlusion,
is covered by NHTSA Option OCC: Occlusion Testing. The development of
acceptance criteria for Option OCC is discussed in a subsequent
subsection.
    As discussed above, the Alliance Guidelines use manual radio tuning
as their reference task. The Alliance Guidelines acceptance criteria
were developed based on this reference task.
    The Alliance Guidelines acceptance criteria were based upon the
85th percentile of driver eye glance performance during manual radio
tuning. As the Alliance points out, the 85th percentile response
characteristics or capability are a common design standard in traffic
engineering. For example, according to the Federal Highway
Administration, all states and most localities use the 85th percentile
speed of free flowing traffic as a basic factor in establishing speed
limits.\95\
---------------------------------------------------------------------------

    \95\ Institute of Transportation Engineers, ``Speed Zoning
Information,'' March 2004, retrieved in August 2011.
---------------------------------------------------------------------------

    The eye glance acceptance criteria times that are in the Alliance
Guidelines are based on a 1987 study by Dingus \96\ and a 1988 study by
Rockwell.\97\ However, neither of these studies actually measured the
total eyes-off-road time associated with manual radio tuning. The
Rockwell study determined that approximately 85 percent of driver eye
glances away from the forward road scene had durations of 1.90 seconds
or less. This value of 1.90 seconds was rounded up by the Alliance to
get their 2.0-second criterion. The Dingus study determined that the
85th percentile for the number of driver eye glances away from the
forward road scene was 9.4 glances. The 9.4 glances value was rounded
up by the Alliance to get 10 glances. The Alliance then multiplied the
10 glances by 2.0 seconds per glance to determine their acceptance
criteria of 20.0 seconds of total glance time.\98\
---------------------------------------------------------------------------

    \96\ Dingus, T.A., Attentional Demand Evaluation for an
Automobile Moving-Map Navigation System, unpublished doctoral
dissertation, Virginia Polytechnic Institute and State University,
Blacksburg, VA, 1987.
    \97\ Rockwell, T.H., ``Spare Visual Capacity in Driving
Revisited: New Empirical Results for an Old Idea,'' in A. G. Gale et
al (editors), Vision in Vehicles II (pp. 317-324, Amsterdam:
Elsevier, 1988.
    \98\ When performing this determination, the Alliance is
treating total glance time to the task as being the same as total
eyes-off-road time.
---------------------------------------------------------------------------

    Based on these studies, the Alliance Guideline's Alternative A have
two acceptance criteria:

    A1. Single glance durations generally should not exceed 2
seconds; and

    A2. Task completion should require no more than 20 seconds of
total glance time to display(s) and controls.\99\
---------------------------------------------------------------------------

    \99\ P. 39, Driver Focus-Telematics Working Group, ``Statement
of Principles, Criteria and Verification Procedures on Driver-
Interactions with Advanced In-Vehicle Information and Communication
Systems,'' June 26, 2006 version, Alliance of Automobile
Manufacturers, Washington, DC.

    For both of the eye glance verification options, the Alliance
---------------------------------------------------------------------------
Guidelines operationalize the A1 and A2 acceptance criteria as follows:

    A task will be considered to meet criterion A1 if the mean of
the average glance durations to perform a task is <= 2.0 sec for 85%
of the test sample. A task will be considered to meet criterion A2
if the mean total glance time to perform a task is <= 20 sec for 85%
of the sample of test participants.\100\
---------------------------------------------------------------------------

    \100\ Ibid, P. 53.

    NHTSA has a concern with these Alliance-developed acceptance
criteria because neither of the studies used as a basis for the
criteria actually measured the total eyes-off-road time associated with
manual radio tuning. Rather, the Alliance estimated it from the data
available in the Dingus and Rockwell studies. NHTSA's concern is with
the way in which the estimate was developed. If 85 percent of driver
eye glances away from the road last for less than 2.0 seconds, the
probability of 10 glances away from the road each having an average
length of 2.0 seconds or greater is very small. As a result, due to
rounding up of both the guideline-recommended length of driver eye
glances and the number of driver eye glances during manual radio
tuning, the Alliance total glance time criterion of 20.0 seconds is not
the 85th percentile value that the Alliance advocates, but instead a
value that approximates the 100th percentile value for manual radio
tuning.
iii. Recent NHTSA Research on Manual Radio Tuning
    To obtain data about driver performance during manual radio tuning,
NHTSA has recently sponsored two experimental studies, one with testing
performed by NHTSA \101\ and one with testing performed by VTTI.
---------------------------------------------------------------------------

    \101\ This study had multiple objectives; a better understanding
of manual radio tuning was just one of the objectives.
---------------------------------------------------------------------------

    The NHTSA study \102\ tested 90 test participants performing 541
instances of manual radio tuning in a 2010 Toyota Prius (trim level V)
connected to a personal computer-based driving simulator. Driving the
simulator required the test participant to follow a lead vehicle moving
at a varying rate of speed. Table 5 presents summary data from the
first (of, typically, 6) manual radio tuning trial for all 90 test
participants. The last two columns represent the respective percentile
values from distributions of each subject's proportion of glances
longer than 1.5 and 2.0 seconds, respectively. The glance data were
computed from eye tracker data. (Comparable data reduced manually from
video footage was also collected for these trials; this found similar
glance durations.)
---------------------------------------------------------------------------

    \102\ Ranney, T. A., Baldwin, G. H. S., Parmer, E., Martin, J.,
and Mazzae, E. N., ``Distraction Effects of Number and Text Entry
Using the Alliance of Automotive Manufacturers' Principle 2.1B
Verification Procedure,'' NHTSA Technical Report number TBD,
November 2011.

Table 5--Summary of Eye Glance Measures During the First Manual Radio Tuning Performed by Test Participants in a
                            2010 Toyota Prius on the NHTSA Driving Simulator (N = 90)
----------------------------------------------------------------------------------------------------------------
                                  Total eyes-off-    Number of      Mean glance     Percent of      Percent of
      Measure or percentile          road time     glances from      duration      glances > 1.5   glances > 2.0
                                     (seconds)         road          (seconds)        seconds         seconds
----------------------------------------------------------------------------------------------------------------
Mean............................            7.11            8.04            0.89              20               3
Median..........................            7.25               8            0.85               0               0
85th............................           10.50              12            1.14              25               0
95th............................           12.70              15            1.39              40              29
100th...........................           16.86              16            2.11              80              50
----------------------------------------------------------------------------------------------------------------

    Items of relevance from Table 5 for NHTSA's determination of its
acceptance criteria include:
     The 85th percentile total eyes-off-road time (TEORT) based
on the first radio tuning trial by each test participant was 10.50
seconds.
     None of the first radio tuning trials by test participants
had a TEORT that exceeded 20.00 seconds. The longest initial radio
tuning trial took 16.86 seconds.
     The 85th percentile mean glance duration (MGD) was 1.14
seconds. For only 1 out of 90 test participants was the mean glance
duration greater than 2.00 seconds during their first trial.
     The 85th percentile proportion of glances longer than 2.00
seconds was zero percent. This means that 85 percent of test
participants performed their first radio tuning trial with no glances
away from the forward roadway of duration longer than 2.0 seconds.
    The NHTSA data collection protocol had test participants perform
the manual radio tuning task multiple times. Table 6 presents the same
data as Table 5 except that Table 6 is based on data from all of each
test participants' radio tuning trials. The first trial data were
analyzed separately, as presented above, since repeatedly performing
the same task was expected to speed up test participant performance of
the task.

 Table 6--Summary of Eye Glance Measures During all Manual Radio Tuning Performed by Test Participants in a 2010
                              Toyota Prius on the NHTSA Driving Simulator (N = 541)
----------------------------------------------------------------------------------------------------------------
                                  Total eyes-off-    Number of      Mean glance     Percent of      Percent of
      Measure or percentile          road time     glances from      duration      glances > 1.5   glances > 2.0
                                     (seconds)         road          (seconds)        seconds         seconds
----------------------------------------------------------------------------------------------------------------
Mean............................            6.49            7.54            0.87              10               3
Median..........................            6.38               7            0.84               0               0
85th............................            9.61              11            1.15              25               0
95th............................           11.97              14            1.39              40              22
100th...........................           20.50              21            2.11              80              50
----------------------------------------------------------------------------------------------------------------

    Differences between the first trial and all trial data are minor.
What differences do exist suggest that radio tuning performance
improves slightly with repeated performance. However, it is important
to note that, while the large number of trials included in Table 6
provides more precision in the estimation of the various metrics, the
construction of this distribution is not formally suitable for use with
inferential statistics, which require independence among all of the
individual data items. In this collection, the use of multiple data
points from each subject is not consistent with the independence
requirement. Items of relevance from Table 6 for NHTSA's determination
of its acceptance criteria include:
     The 85th percentile TEORT value for repeatedly performing
radio tuning was 9.61 seconds. (Reduced from the 10.50 seconds found
for the first trial data.)
     Only 1 out of 541 total radio tuning trials had a TEORT
value greater than 20.00 seconds. The second longest TEORT value was
17.28 seconds.
     The 85th percentile mean glance duration was 1.15 seconds.
For only 1 out of 541 trials was the mean glance duration greater than
2.00 seconds. The second longest mean glance duration was 1.85 seconds.
     The 85th percentile proportion of glances longer than 2.00
seconds was zero percent. Although not shown in Table 6, the 90th
percentile value for this metric was 14 percent. This means that 90
percent of 541 radio tuning trials were accomplished with no more than
14 percent of the glances away from the forward roadway being longer
than 2.00 seconds.
    The VTTI radio tuning study had two testing phases. During Phase I,
test participants drove each of four vehicles on the VTTI Smart Road
while following a lead vehicle traveling at a constant speed of 45 mph.
One vehicle was tested using both of its two available methods for
tuning the radio, resulting in a total of five test conditions. The
five vehicles/configuration conditions tested were:
    1. 2005 Mercedes R350
    2. 2006 Cadillac STS
    3. 2006 Infiniti M35
    4. 2010 Chevrolet Impala with rotary knob tuning
    5. 2010 Chevrolet Impala with push button tuning
    During Phase II, test participants drove each of two vehicles on
the VTTI Smart Road while following a lead vehicle traveling during one
lap at a constant speed of 45 mph and during another lap at a variable
speed.\103\ One vehicle was again tested using both of its two
available methods for manually tuning the radio resulting in a total of
three test conditions. The three vehicles/configuration conditions
tested were:
---------------------------------------------------------------------------

    \103\ The variable speed profile of the lead vehicle for this
second lap was similar to the one used by NHTSA during testing on
their driving simulator. There were two differences. First, slowing
down the lead vehicle on the NHTSA driving simulator was
accomplished by having the driver remove his/her foot from the
throttle pedal and allowing the vehicle to coast. However, due to
the vertical profile of the VTTI Smart Road, when going downhill,
the lead vehicle driver had to brake to produce the desired speed
variation. The resulting brake lights are likely to have impacted
the test participants' following behavior/performance. Second, the
speed reduction profile was more step-wise than the one used in the
simulator, since the lead vehicle speed was controlled by a trained
driver, not by automated means.
---------------------------------------------------------------------------

    1. 2010 Chevrolet Impala with rotary knob tuning
    2. 2010 Chevrolet Impala with knob/button tuning
    3. 2010 Toyota Prius (exact same vehicle as tested by NHTSA)
    A total of 43 participants between the ages of 45 and 65 took part
in this study. This participant sample was comprised of two separate
participant groups, as data collection occurred in phases listed above.
Invalid data points were removed, yielding at least 20 participants
with complete data for each phase as well as some participants with
missing data.
    Data were analyzed for the longest duration manual radio tuning
trial for each test participant for each vehicle/configuration. Data
for a total of 228 manual radio tuning trials were obtained and
analyzed.
    Table 7 summarizes the eye glance measures that were calculated by
VTTI for the manual radio tuning trial of longest duration performed by
each test participant in each of the vehicles/tuning methods/lead
vehicle speed profile conditions. The values shown for Total Glance
Time to Task, Total Eyes-Off-Road Time, and Average Duration of
Individual Glances to Device are all 85th percentile values. The
Duration of Longest Glance to Device values are the longest glances to
the device that were made for that vehicle/tuning method/lead vehicle
speed profile for any of the radio tuning trials that were analyzed.

   Table 7--85th Percentiles of Eye Glance Measures During Manual Radio Tuning Trials Performed by in Various
                           Vehicles Test Participants on the VTTI Smart Road (N = 228)
         [Duration of Longest Glance to Device and Total Number of Data Points are not 85th percentiles]
----------------------------------------------------------------------------------------------------------------
                                                                                Duration of
Vehicle, tuning method, and lead   Total glance   Total eyes-off-   Mean glance   longest glance   Total number
      vehicle speed profile        time to task      road time       duration        to device    of data points
                                      (sec.)          (sec.)          (sec.)          (sec.)           (--)
----------------------------------------------------------------------------------------------------------------
Cadillac STS--Knob Tuning--                 15.9            16.3             1.7             2.9              21
 Constant Speed.................
Chevrolet Impala--Button Tuning--           13.2            13.9             1.3             2.4              41
 Constant Speed.................
Chevrolet Impala--Knob Tuning--              7.8             8.1             1.4             2.2              41
 Constant Speed.................
Chevrolet Impala--Button Tuning--           11.5            12.3             1.2             2.3              20
 Varied Speed...................
Chevrolet Impala--Knob Tuning--              8.4             8.5             1.4             2.4              20
 Varied Speed...................
Infiniti M35--Button Tuning--               17.6            17.6             1.7             4.5              21
 Constant Speed.................
Mercedes R350--Button Tuning--              15.4            16.6             1.4             2.6              22
 Constant Speed.................
Toyota Prius--Knob Tuning--                 10.3            11.1             1.4             2.4              21
 Constant Speed.................
Toyota Prius--Knob Tuning--                 11.3            11.3             1.6             2.7              21
 Varied Speed...................
All VTTI Data...................            11.6            11.8             1.5             2.5             228
----------------------------------------------------------------------------------------------------------------

    Items of relevance from Table 7 for NHTSA's determination of its
acceptance criteria include:
     The 85th percentile Total Glance Time to Task (TGT) for
performing manual radio tuning varied from 7.8 to 17.6 seconds
depending upon the vehicle, tuning method, and lead vehicle speed
profile. The 85th percentile TGT for all of the VTTI radio tuning data
was 11.6 seconds.
     The 85th percentile Total Eyes-Off-Road Time (TEORT) for
performing manual radio tuning varied from 8.1 to 17.6 seconds
depending upon the vehicle, tuning method, and lead vehicle speed
profile. The 85th percentile TEORT for all of the VTTI radio tuning
data was 11.8 seconds.
     The 85th percentile TEORT exceeded the 85th percentile TGT
times by 0.0 to 1.2 seconds with an average increase of 0.2 seconds.
     The 85th percentile mean glance durations ranged from 1.2
to 1.7 seconds depending upon the vehicle, tuning method, and lead
vehicle speed profile.
iv. Development of NHTSA's Eye Glance Acceptance Criteria
    NHTSA proposes to base the acceptance criteria in these Guidelines
on test participants' Eyes-Off-Road Time (EORT) during task
performance. This differs from existing Alliance and JAMA Guidelines
which assess task-related eye glance behavior based upon just those eye
glances to the device upon which the task is being performed.\104\
---------------------------------------------------------------------------

    \104\ However, the Alliance Guidelines do not consistently
distinguish between test participant glances to the device being
tested and test participant eye glances away from the forward
roadway and, in places, appear to treat the two as interchangeable.
For example, in the discussion on p. 42 of the Alliance Guidelines
on the basis for the Alliances A2 acceptance criterion of 20
seconds, the phrase ``mean number of glances away from the road
scene'' is used. However, this is equated to test participant
glances to the device being tested to develop the 20 seconds
acceptance criterion.
---------------------------------------------------------------------------

    NHTSA proposes to use EORT because we would like to use eye tracker
data to determine whether a task meets the eye glance criteria.
However, based upon the experiences of NHTSA, eye tracker data do not
have quite enough accuracy to reliably characterize whether eye glances
are focused toward the device upon which the task is being performed or
toward some other in-vehicle location.\105\ Eye tracker data do have
sufficient accuracy to accurately characterize test participant eye
glances focused away from the forward roadway.
---------------------------------------------------------------------------

    \105\ Ranney, T.A., Baldwin, G.H.S., Vasko, S.M., and Mazzae,
E.N., ``Measuring Distraction Potential of Operating In-Vehicle
Devices,'' DOT HS 811 231, December 2009. NHTSA's eye glance
measurement technology has been upgraded since this report was
written but the specific eye position limitation noted in that
report continues to be a problem. The report ``Developing a Test to
Measure Distraction Potential of In-Vehicle Information System Tasks
in Production Vehicles'' by Ranney, T.A., Baldwin, G.H.S., Parmer,
E., Domeyer, J., Martin, J., and Mazzae, E. N., DOT HS 811 463,
November 2011, discusses NHTSA's most recent work to upgrade its eye
glance measurement technology.
---------------------------------------------------------------------------

    Total EORT, or the cumulative duration of eye glances away from the
roadway during task performance, will always equal or exceed the Total
Glance Time to Task (TGT). For the VTTI testing, the 85th percentile of
this difference ranged from 0.0 to 1.2 seconds with an average increase
of 0.2 seconds. Therefore, basing the test acceptance criteria on TEORT
instead of TGT gives a slight increase in test stringency. However,
this is partially compensated for by NHTSA's use of a reference task to
determine overall test stringency.
    NHTSA finds reasonable the Alliance's technique of using the 85th
percentile of driver eye glance measures while performing manual radio
tuning as a way to set acceptance criteria for testing to determine if
a task is unreasonably distracting. As the Alliance points out, the
85th percentile response characteristics or capability are a common
design standard in traffic engineering. Other existing guidelines do
not appear to use this reference task technique for determining
acceptance criteria.
    Occlusion testing (discussed in greater detail in a subsequent
subsection) involves unoccluded vision durations of 1.5 seconds. Using
the previously discussed 75 percent field factor for occlusion testing
versus driving simulator eyes-off-road time, each 1.5-second unoccluded
period corresponds to 2.0 seconds of driving simulator eyes-off-road
time. Therefore, specified acceptance criteria involving eyes-off-road
time should be a multiple of 2.0 seconds.
    The NHTSA and VTTI manual radio tuning testing summarized in Tables
5 through 7 found 85th percentile Mean Glance Durations (MGD) that
ranged from 1.1 to 1.7 seconds depending upon the vehicle, tuning
method, test venue, and lead vehicle speed profile. All of these values
round to 2.0 seconds (equivalent to a shutter open time of 1.5 seconds
during occlusion testing). Therefore one proposed NHTSA acceptance
criterion is that, for 85 percent of test participants, the mean
duration of all individual eye glances away from the forward road scene
should be less than 2.0 seconds while performing the secondary task.
Since NHTSA is proposing to test a sample of 24 subjects, for at least
21 of the 24 test participants (85 percent rounded up to the next whole
number of test participants), the mean of all eye glances away from the
forward road scene should be less than 2.0 seconds while performing the
secondary task. The proposed NHTSA mean eye glance duration criterion
then is:
     For at least 21 of the 24 test participants, the mean
duration of all individual eye glances away from the forward road scene
should be less than 2.0 seconds while performing the secondary task.
    The above acceptance criterion only constrains the mean of the eye
glance distribution. This is necessary but, NHTSA believes, not
sufficient. As pointed out by Horrey and Wickens:

    In general, the unsafe conditions that are likely to produce a
motor vehicle crash reside not at the mean of a given distribution
(in other words, under typical conditions), but rather in the tails
of the distribution.\106\
---------------------------------------------------------------------------

    \106\ Horrey, W.J., and Wickens, C.D., ``In-Vehicle Glance
Duration: Distributions, Tails, and Model of Crash Risk,''
Transportation Research Record, Journal of the Transportation
Research Board, No. 2018, Transportation Research Board of the
National Academies, pp. 22-28, Washington, DC, 2007.

    To ensure safety, it is also necessary to have another acceptance
criterion that minimizes the above 2.0-seconds tail of the eye glance
distribution.
    The acceptance criterion that NHTSA is proposing is designed to
directly limit the tail of the eye glance distribution. The proposed
eye glance distribution tail-limiting criterion, for 85 percent of test
participants, limits the percentage of their long (more than 2.0
seconds) eye glances away from the forward road scene while performing
the secondary task to no more than 15 percent of their total number of
eye glances away from the road.
    Typically, the number of eye glances away the forward road scene
will be fairly low for any task, function, or feature that passes all
of the eye glance criteria. For example, if the average eye glance
duration is 1.5 seconds, a task can have a maximum of eight eye glances
away the forward road scene and meet the TEORT acceptance criterion
(discussed below). Therefore, the method used for rounding when
calculating the 15 percent of eye glances value is important.
    NHTSA has tentatively decided that, for any task that requires at
least two \107\

eye glances away from the forward road scene, it should be acceptable
for at least one of these eye glances to exceed 2.0 seconds in duration
(of course, the other two acceptance criteria would also have to be
met). This can be accomplished by always rounding up when calculating
the guideline-recommended number of eye glances exceeding 2.0 seconds
in duration. The proposed NHTSA eye glance distribution tail limiting
criterion then is:
---------------------------------------------------------------------------

    \107\ For a task that only requires one glance away from the
forward roadway, the mean glance duration criterion cannot be met
unless that glance is less than 2.0 seconds long. Therefore, the
proposed NHTSA eye glance distribution tail limiting criterion does
not need to have a special case for one glance tasks.
---------------------------------------------------------------------------

     For at least 21 of the 24 test participants, no more than
15 percent (rounded up) of the total number of eye glances away from
the forward road scene should have durations of greater than 2.0
seconds while performing the secondary task.
    The NHTSA and VTTI manual radio tuning testing summarized in Tables
5 through 7 found 85th percentile Total Eyes-Off-Road Times (TEORT)
values that ranged from 8.1 to 17.6 seconds depending upon the vehicle,
tuning method, test venue, trial, and lead vehicle speed profile.
    NHTSA is proposing to perform driver eye glance measurement in
conjunction with a driving simulator protocol. For test participants
driving a 2010 Toyota Prius, NHTSA measured a 85th percentile TEORT
value of 10.5 seconds for the first manual radio tuning trial performed
and 9.6 seconds using data from all trials. It is not clear which of
these values best typifies normal driving since drivers are generally
familiar with their own vehicle's radio, and have tuned it many times
but generally not consecutively.
    The VTTI data collected under conditions that most closely match
the NHTSA experimental conditions for testing are those collected on
VTTI's Smart Road using a 2010 Toyota Prius (VTTI tested the exact same
vehicle) following a lead vehicle with varying speed. The VTTI measured
85th percentile TEORT for this condition is 11.3 seconds (versus
NHTSA's 10.5 seconds). From this data, it appears that driving
simulator measured TEORT values may be slightly shorter than ones
measured while driving on the Smart Road. However, the two studies'
results are similar enough (considering the variability present in
testing of this sort) that it is reasonable to analyze both sets of
results together and determine an overall TEORT.
    The 85th percentile from the consolidated NHTSA and VTTI manual
radio tuning data is 11.3 seconds. For compatibility with occlusion
testing, the maximum TEORT needs to be a multiple of 2.0 seconds. The
nearest multiple of 2.0 seconds to 11.3 seconds is 12.0 seconds.
Therefore NHTSA is proposing that the acceptance limit for TEORT for
Option EGDS: Eye Glance Testing Using a Driving Simulator be 12.0
seconds. In other words, tasks with an 85th percentile TEORT greater
than 12.0 seconds should not be accessible by the driver while
driving.\108\
---------------------------------------------------------------------------

    \108\ For the purposes of these NHTSA Guidelines, ``while
driving'' is defined as any time the vehicle's engine is turned on
and its transmission is not in ``Park'' (for automatic transmission
vehicles; for manual transmission vehicles change this to the
transmission is not in ``Neutral'' with the parking brake engaged).
---------------------------------------------------------------------------

    As has been mentioned, the Alliance Guidelines include a TEORT
acceptance limit of 20.0 seconds for Principle 2.1, Alternative A. The
JAMA Guidelines include a TEORT acceptance limit of 8.0 seconds.
NHTSA's value of 12.0 seconds is between these two values. NHTSA
prefers the 12.0 second limit to either of the other two guidelines'
values because the NHTSA value is based on more recent, more thorough,
research.
    Since NHTSA is proposing to test a sample of 24 test participants,
for at least 21 of the 24 test participants (85 percent rounded up to
the next whole number of test participants), the TEORT should be less
than 12.0 seconds while performing the secondary task. The proposed
NHTSA total eye glance duration criterion then is:
     For at least 21 of the 24 test participants, the sum of
the durations of each individual participant's eye glances away from
the forward road scene should be less than, or equal to, 12.0 seconds
while performing the secondary task one time.

N. Human Subject Selection for Guideline Testing

    The NHTSA Guidelines suggest that the following test participant
sample composition criteria be used for testing performed to determine
whether a device should be locked out under the NHTSA Guidelines:
    1. To ensure that in-vehicle device secondary tasks can be
performed by virtually the entire range of drivers without being
unreasonably distracting, the recommended age range for test
participants is 18 years and older. NHTSA research has shown that
restricting test participant age range can improve test
repeatability.\109\ The lower limit, 18 years of age, is due to
concerns about testing with minors. There is no upper limit, however,
organizations may set an upper age limit (such as 65 years old) for
their testing if they can easily find the needed test participants and
they have health concerns about testing with elderly test participants.
---------------------------------------------------------------------------

    \109\ Ranney, T. A., Baldwin, G. H. S., Parmer, E., Martin, J.,
and Mazzae, E. N., ``Distraction Effects of Number and Text Entry
Using the Alliance of Automotive Manufacturers' Principle 2.1B
Verification Procedure,'' NHTSA Technical Report number TBD,
November 2011.
---------------------------------------------------------------------------

    2. Continuing with NHTSA's goal of ensuring that in-vehicle device
tasks can be performed by the entire age range of drivers without being
unreasonably distracting, the NHTSA Guidelines recommend that out of
each group of 24 test participants used for testing, there should be
     Six test participants 18 through 24 years old, inclusive,
and
     Six test participants 25 through 39 years old, inclusive,
and
     Six test participants 40 through 54 years old, inclusive,
and
     Six test participants 55 or more years old.
    This should ensure adequate representation by a broad age range of
test participants in each sample of subjects.
    The above age ranges are partially based on the age distribution of
drivers in the United States. NHTSA is focusing on the age distribution
of drivers rather than the age distribution of drivers involved in
fatal crashes because:
     The age distribution of drivers involved in fatal crashes
due to electronic device distraction is not necessarily the same as the
age distribution of drivers involved in all fatal crashes. NHTSA
currently does not know the age distribution of drivers involved in
fatal crashes due to electronic device distraction.
     The age distribution of drivers involved in fatal crashes
due to electronic device distraction may change in the future as new
electronic devices are introduced into service.
    Table 8 shows the percentage of United States drivers 18 years of
age and older in each of the four test participant age ranges.
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    \110\ http://www.fhwa.dot.gov/policyinformation/statistics/2009/dl20.cfm.

 Table 8--Percent of United States Drivers 18 Years of Age and Older in
                          Each Age Range \110\
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                                             Percent of United States
               Age range                       drivers in age range
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18-24..................................  11.4%
25-39..................................  26.8%
40-54..................................  29.7%
55 and older...........................  32.1%
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    The 18 through 24 years old, inclusive, age range is
overrepresented in test samples relative to their numbers in the
general driving population. There are two reasons for this. First,
drivers in

the 18 through 24 age range have a higher rate of fatalities (per
100,000 drivers in that age range \111\ or per 100 million vehicle
miles traveled \112\) than do drivers that are 25 years of age or
older. Second, at least anecdotally, younger drivers are more frequent
user of electronic technology than are older drivers. Therefore, NHTSA
believes that this age range should be overrepresented in each test
participant sample.
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    \111\ National Highway Traffic Safety Administration, ``Traffic
Safety Facts 2008,'' NHTSA Technical Report DOT HS 811 170, 2010.
    \112\ United States Government Accountability Office, ``Older
Driver Safety, Knowledge Sharing Should Help States Prepare for
Increase in Older Driver Population,'' Report to the Special
Committee on Aging of the United States Senate, GAO-07-413, April
2007.
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    The 55 years and older age range is underrepresented in test
samples relative to their numbers in the general driving population.
While NHTSA considers it important that advanced electronic device
tasks be tested using drivers in this age range, as mentioned above,
older drivers are less frequent users of electronic technology than are
younger drivers. Therefore, NHTSA is proposing to underweight this age
range with six test participants rather than the eight called for by
their numbers in the general driving population.
    NHTSA solicits comments on the age range and distribution of test
participants that are recommended to be in each test participant
sample. We could use the age distribution of drivers involved in fatal
crashes as the primary factor in determining the age range and
distribution of test participants. This would result in somewhat
different age ranges and distributions than are listed above. Would
this be better for ensuring safety while driving and using electronic
devices?
    3. NHTSA also wishes to ensure that drivers of both genders be able
to safely utilize in-vehicle devices. The United States driver
population is 49.7 percent male and 50.3 percent female. For the
relatively small test participant samples used for distraction testing,
this implies that test participant samples should be evenly divided
between men and women (i.e., each sample of 24 test participants should
be balanced in gender overall and within each age range).
    4. Another of NHTSA's concerns relates to ensuring that test
participants are impartial with regard to the testing. To ensure
fairness, test participants should not have any direct interest,
financial or otherwise, in whether or not any of the devices being
tested meets or does not meet the acceptance criteria. Therefore, NHTSA
has added test participant impartiality criteria to its NHTSA
Guidelines.
    While auto manufacturers may have multiple categories of employees
that are not involved in vehicle systems or component development,
NHTSA believes that automaker employees will tend to be generally more
knowledgeable about vehicles and their current features than the
average member of the public. With this additional knowledge of
vehicles and their latest features, the employees may perform better in
testing due to this exposure to the automotive industry. Therefore we
feel that this impartiality criterion is essential to ensure that test
results represent the performance of average U.S. drivers. We welcome
comments on any available strategies that automakers may implement to
ensure impartial test participation by employees.

O. Occlusion Test Protocol

    NHTSA is proposing that its Option OCC: Occlusion Testing test
protocol be the same as that specified in ISO 16673:2007.\113\ ISO
16673:2007 specifies a viewing interval (shutter open time) of 1.5
seconds followed by an occlusion interval (shutter closed time) of 1.5
seconds. NHTSA has selected the use of the ISO test protocol for its
occlusion test protocol in the interests of promoting international
regulatory harmonization.
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    \113\ International Standard 16673:2007, ``Road Vehicles--
Ergonomic Aspects of Transport Information and Control Systems--
Occlusion Method to Assess Visual Demand due to the use of In-
Vehicle Systems.''
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    NHTSA's past occlusion testing was performed with a viewing
interval (shutter open time) of 1.5 seconds followed by an occlusion
interval (shutter closed time) of 1.0 second. NHTSA is performing a
study during the summer of 2011 to examine what effects, if any, this
change to the length of the occlusion interval has on the results of
occlusion testing. This study will also ensure that there are no
unforeseen difficulties in performing occlusion testing using the ISO
16673:2007 test protocol.
    ISO 16673:2007 states that occlusion testing results need to be
corrected for system response delays that are greater than 1.5
seconds.\114\ However, since the NHTSA Guidelines specify that the
maximum device response time for a device input should not exceed 0.25
second, no correction is needed for occlusion testing performed under
the NHTSA Guidelines.
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    \114\ Ibid, P. 13.
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    NHTSA is proposing to set the maximum recommended total viewing
interval (total shutter open time) for a task to be accessible to the
driver while driving at 9.0 seconds. As was previously discussed, NHTSA
is proposing to set the maximum recommended total glance time (time
during which the driver's eyes are looking at the device upon which the
task is being performed) for a task to be accessible to the driver
while driving for Option EGDS: Eye Glance Testing Using a Driving
Simulator at 12.0 seconds of total eyes-off-road time. The acceptance
criteria for Option OCC: Occlusion Testing should be consistent with
the Option EGDS acceptance criteria. Applying the earlier explained
field factor of 75 percent to the 12.0 seconds of total eyes-off-road
time criteria that NHTSA is proposing for Option EGDS: Eye Glance
Testing Using a Driving Simulator gives a maximum permitted total
shutter open time for the NHTSA Guidelines Option OCC: Occlusion
Testing of 9.0 seconds.

P. Task Performance Errors During Testing

    Reaching the desired end state of a secondary task is generally
only possible if the driver follows the correct steps to complete the
task and makes no mistakes. If the driver presses the wrong button or
inputs an incorrect character, a correction typically must be made in
order to reach the desired end state. An interface associated with
frequent input errors by the driver could reasonably be considered a
greater source of distraction than one for which task performance is
performed without errors. Therefore, for the purposes of these NHTSA
Guidelines only data from ``error-free'' test trials performed by test
participants should be used for determining whether a task is suitable
for performance while driving. Using only data from error-free test
trials improves testing repeatability.
    The precise definition of an error during device testing is
difficult to develop. NHTSA proposes that an error would be considered
to have occurred during a test trial if the test participant has to
backtrack or delete already entered inputs. If the device can
accommodate an incorrect entry without requiring backtracking and extra
inputs beyond those necessary to reach the desired end state of the
task, then no error would be deemed to have occurred. For example,
suppose that a task on a device could be accomplished either by
pressing Button ``A'' or by pressing first Button ``B'' and then Button
``C.'' If a test participant were asked to perform this task, either

pressing Button ``A'' or pressing first Button ``B'' and then Button
``C'' would result in a valid trial. If however, the test participant
first pressed Button ``B,'' then reset the device, and then pressed
Button ``A'' an error would have occurred.
    A record should be kept during testing as to whether one or more
errors occurred during each test trial. If errors occur during more
than 50 percent of test trials while testing a sample of test
participants, then that task is deemed an ``unreasonably difficult
task.'' Unreasonably difficult tasks are not recommended for
performance while driving and should be locked out. (Note that in order
to check NHTSA's acceptance criteria; it is necessary for 24 test
participants to successfully complete each task. This may require
testing more than 24 subjects.)

Q. Limited NHTSA Guidelines for Passenger Operated Equipment

    The NHTSA Guidelines are appropriate primarily for devices that are
intended to be operated by the vehicle driver. For the sake of clarity,
NHTSA believes it necessary to make a few general statements about
passenger operated equipment.
    The NHTSA Guidelines should be appropriate for any devices that the
driver can easily see and/or reach. For any in-vehicle device that is
within sight and reach of the driver (even if it is intended for use
solely by passengers), any task that has associated with its
performance an unacceptable level of distraction should be locked out
whenever the vehicle's engine is on and its transmission is not in
``Park'' (the vehicle's transmission in ``Neutral'' and parking brake
engaged for manual transmission vehicles).
    The NHTSA Guidelines are not appropriate for any device that is
located fully behind the front seat of the vehicle. Similarly, the
NHTSA Guidelines are not appropriate for any front-seat device that
cannot reasonably be reached or seen by the driver.

VII. Implementation Considerations for the NHTSA Guidelines

A. Current Vehicles That Meet the NHTSA Guidelines

    All members of the Alliance of Automobile Manufacturers have
committed themselves to producing vehicles that meet the Alliance
Guidelines. Five years have passed since the current version of the
Alliance Guidelines was issued and NHTSA expects that most current
vehicle models produced by Alliance members meet the Alliance
Guidelines. However, this is an expectation based on statements by the
Alliance's members and is not based on any NHTSA testing of recently
designed vehicle models.
    Some automobile manufacturers that are not members of the Alliance
(e.g., Honda) have also committed to producing vehicles that meet the
Alliance Guidelines. However, this commitment was made in 2010;
therefore, most of their vehicles may not yet meet the Alliance
Guidelines' recommendations.
    Given the many common elements and details between the NHTSA
Guidelines and the Alliance Guidelines, NHTSA believes that many in-
vehicle device tasks will either meet the recommendations of these
proposed NHTSA Guidelines or be close to doing so. The changes to
existing devices and/or vehicles that already meet the Alliance
Guidelines so as to make them meet the NHTSA Guidelines are expected to
be minor.
    There is no time frame in which vehicle manufacturers are expected
to produce vehicles that meet these guidelines; meeting them is
strictly voluntary. However, NHTSA believes that manufacturers will
take the initiative to implement these guidelines in an effort to
improve safety. Manufacturers choosing to implement these guidelines
for existing vehicle models would likely make any necessary changes to
meet the guidelines when a vehicle model undergoes a major revision.
Typically, major revisions occur on about a five-year cycle for
passenger cars and less frequently for light trucks. NHTSA believes
that it would be feasible for manufacturers to make the necessary
changes implementing these guidelines for existing vehicle models that
undergo major revisions two or more years after the final issuance of
these guidelines. Likewise, NHTSA believes it would be feasible for new
vehicle models that come onto the market two or more years after the
final issuance of these guidelines to meet them.

B. Expected Effects of the NHTSA Guidelines

    The main effects that NHTSA hopes to achieve through its NHTSA
Guidelines are better designed vehicles and integrated electronic
device interfaces, neither of which exceeds a reasonable level of
complexity for visual-manual secondary tasks. This will be accomplished
through multiple recommendations that will discourage device interfaces
that lack evidence of sound human factors principles in their designs.
One important recommendation recommends a limit for allowable total
eyes-off-road time for any one task. The NHTSA Guidelines would
discourage the introduction of egregiously distracting integrated
devices and non-driving tasks.
    The NHTSA Guidelines recommend against designing in-vehicle
electronic systems that allow drivers to perform the following
activities while the vehicle is ``moving'': \115\
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    \115\ More specifically, the NHTSA Driver Distraction Guidelines
recommend disabling unreasonably distracting tasks/device unless