Will building more roads in Austin decrease traffic?

austin traffic solutions

(Original photo by NEFF CONNER/nffcnnr on flickr used under Creative Commons)

You can’t go a day without someone in Austin complaining about traffic. We do it on Facebook. The  mainstream media does it. Even Governor Perry did it last week. And the most common responses to complaints regarding traffic in Austin are:

“We need more lanes.”

“We need more roads.”

These people are frustrated because Austin appears to be slow to “address the problem” and construct new roadways. With my background in transportation planning, I can tell you that building more roads will not solve the traffic problem. Here’s why.

Building a new freeway: An example from New York

Let’s say you live in New York. It’s rush hour, and you want to go to a hip new restaurant in Queens from your house in Manhattan. You know driving will take an eternity, so you weigh your options.

You could A) ride the subway and avoid traffic; B) wait until later and drive when traffic clears up; or C) decide not to make the trip at all and eat somewhere nearby instead. In determining what to do, you consider how you get there, when to go, or if you go at all. This rationalizing causes something called Triple Convergence, or Induced Demand, and it is at the root of urban transportation behavior.

Ok, so let’s say that NYC builds a beautiful new flyover freeway that goes from your house in Manhattan directly to Queens. What happens when this new road opens?

At first, there is a temporary leveling of cars on the road network as drivers change their old routes to this more direct one. All of a sudden, traffic across the city opens up and balances out, right?

Not so fast: Now, people like you who would have ridden the subway see a faster route and decide it is now more convenient to drive. Hopping in their cars, they quickly increase the traffic load. And the drivers who were going to make those trips at off-peak hours? They now find it convenient enough to make the trip at rush hour. And the people who weren’t sure they’d make smaller trips like shopping, visiting friends, trying a new restaurant, or stopping by the office also decide it’s more convenient enough to hop in their cars.

Now that all of those people have shifted their routes, their modes of transportation, their times, and their travel decisions, the new road capacity is effectively congested, with all roads levels as high as before construction. After so much cost, time, and inconvenience, everyone is dumbfounded by the lack of relief.

The lesson here is that in a growing city, demand will always be greater than capacity. And even in a world with unlimited money, construction workers, and right-of-way, we still would not be able to build ourselves out of congestion. Instead, we’re actually throwing money away on projects that provide us with nothing but additional debt.

More roads, more access, more traffic: The Hays County example

Induced Demand can be compounded when roads open up access to previously remote areas. As we build these new roads, the improved access increases the desirability of the land surrounding those areas. For example, we can look at the proposal that many road advocates currently support: the expansion of State Highway 45, shown below.

Proposed State Highway 45 to Hayes County

(Uncredited schematic from THE AUSTIN CHRONICLE)

This additional capacity would certainly increase travel options from Hays County into Austin, bridging the gaps between the cities and shortening the commute. As a result, demand for housing in northern Hays County will soar, and homebuyers will flock to the county’s low taxes and 15-minute shorter commute!

The reality, however, is quite different. Between induced demand and the overall increase in commuters from the area, there is actually an overall increase in congestion. The additional road, which cost us all quite a lot of money to construct and even more to maintain, will result in more traffic than before the road was constructed.

Solving the Problem

All of this can be distressing to commuters. If new roads and additional lanes will not solve traffic problems, what can we do? The answer, of course, is that there is no single magic bullet. To relieve congestion and reduce travel times, Austin will need to rely on “a thousand small cuts,” so to speak.

In my next post, I’ll take a look 7 simple methods we can implement to improve transportation in Austin.

What do you think? Should we build more roads?

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About Mark Gilbert

East Austinite, Certified Urban Planner, hiker, food-lover, and coffee-savvy traveler committed to developing a sustainable, high quality environment.

17 thoughts on “Will building more roads in Austin decrease traffic?

  1. Tim

    I think a better example would be going to the mall. Right now, people would call you crazy if you said you were thinking about going to the mall during rush hour. But if suddenly traffic started moving faster you’d think, “Hey I can go to the mall, I’ve got time right now”. Boom, more cars on the road. Slower traffic. Why is rush hour worse in the evening than the morning? Because most stores aren’t open in the morning, so you can’t decide to go pick something up at Academy during rush hour.

    And don’t even get me started on schools. Somewhere between 5,000-9,000 trips per day in Austin are parents taking kids to transfer schools. A better solution might be figuring out how to provide bus service for transfer students.

  2. superspeck

    We’re moving to Austin from Houston. Austinites complaining about bad traffic is somewhat amusing to me. Sure, there’s lots of chokepoints and lots of traffic lights. At least you don’t have roads that simply become parking lots for hours. My fiancée has a 2 mile commute. It’s faster to do it by bicycle, even if you deviate to the greenway. And your roads don’t have random sinkholes opening in them like major streets (e.g. Kirkwood and Briar Forest) in West Houston do.

    Most of the traffic lights could be fixed by a holistic review of chokepoints in the entire network and doing some creative road planning: Let’s try an occasional right turn lane, for instance. Get rid of stoplights that are known to have half hour waits at them. Create grade separations. The new interchange at 2222 and 360 is a great example. The 360/71/1 interchange is an example of how not to do it. But, oh, wait, I know: Those aren’t a toll road, so you don’t have the same push behind it.

    Better yet, counties and cities could work together to control growth. Try putting a throttle on growth by forming a cross-county task force like Portland, Oregon’s Metro and letting the pace of road and school construction catch up with population growth for a few years.

    • DMR

      I just moved to Houston from Austin, and I would say the exact opposite. I have come to a complete stop countless times in Austin on Mopac and 35, but have yet to come to a stop on a Houston highway yet. I often just resorted to trudging it down Lamar, or cut through the neighborhoods west of Mopac.

    • Alejandra Gomez

      I agree, prepare yourself for worst traffic in Austin, I also moved from Houston and trust me it really really sucks.

  3. Ryan

    Wide adoption of alternative and flex schedules combined with distributed campuses/professional work cafes and work from home programs could cut down on rush-hour traffic.

  4. H Would

    Interesting insight. Now build more roads and prove all the naysayers wrong. Screw the debt. Austin taxpayers have, and will continue to, supplement growth with their tax dollars. Growth in Austin does not pay for itself, as it does in many metro areas throughout the country. Raise taxes, pay for the growth, if you can’t afford it, move somewhere else. I prefer private airways, but I can’t afford it, so I take Southwest.

  5. Peter Bailey

    Totally agree with your points re: more roads = more traffic and need urgent need for rail transit to divert growth from exurbs.

    IMHO the only med-long term workable solution is to absorb as much of new population growth as possible with substantially increased near-core density with *both* mid-rise and high-rise development (esp. E. Austin and /Riverside S Austin which are relatively un-/under-developed), with the increased density to enable viable light rail transit (e.g. through E Austin looping up to Mueller and/or line for S. to N. Lamar. The alternative (which we are already defaulting to) is filling in the entire inside of the SH-130 loop with mile after mile of low density strip malled vapid mediocrity, aka let’s make Austin into Houston/Dallas!

    The core point that transit opponents willfully refuse to recognize is that Austin’s existing highway layout is very sharply constrained and in many cases simply can’t be fixed (e.g. no space for extra lanes on Hwy 183 S.of Great Hills to IH-35, super expensive inner burb real estate on 2222, 2244, bad IH-35 inner core layout), since the key bottlenecks are in the core. That means no or ultra-expensive/high-disruption highway expansion.

    To your point, willfully ignorant projects like SH-45 that are trying to mitigate core congestion by exurb highway expansion will only backfire by further aggravating core congestion. What’s happening is that the very understandable frustration of commuters living in Cedar Park/Georgetown/Lakeway/Buda is creating irresistable pressure To Do Something To Fix My Highway, i.e. exactly the wrong thing guaranteed to make the problem worse, combined w. a bag of hammers stupid political culture even in Austin that anything that doesn’t burn gas and/or spends gov’t dollars for transit on poors and/or pinko metrosexuals is a waste of money. The actual truth is that building dense neighbourhoods w. transit, and using market incentives like tolls and much higher parking fees to try to discourage traffic. i.e. The only affordably workable long term solution is to build transit to Get 100,000′s Of People Off My Highway, vs. Building More Highways.

    I count myself extremely lucky to be living in E. Austin and telecommuting or flying out of Bergstrom, so I’ve planned my home and work arrangements to avoid dealing w. any of this. I am constantly having to guard myself from Schadenfruede and you’re-all-screwed-too-bad-so-sad cynicism. But it is going to take a huge education effort and really strong leadership to get people to choose the only workable path forward, and I am quite skeptical Austin can turn the corner on this.

  6. Dano

    This will probably sound goofy, but hear me out…Part of the solution is simply smaller vehicles. Think if all the single-passenger commuters in large-ish vehicles suddenly started driving small electric cars half to a third of the size of their current car. The road capacity would be more than doubled without building a single new road. Such a car does not currently exist. NEVs (neighborhood electric vehicles) are close but need more range and speed. They would typically be two passenger, with some room for groceries/tools/backpacks. Change the freeway configuration to provide two protected lanes for these vehicles, separated from the larger cars. Parking would be effectively increased, too. The idea is that you make driving smaller vehicles more convenient and efficient. I personally believe this is a more realistic solution. I don’t see us giving up the convenience of cars anytime soon and light rail does not seem to provide a very good cost/benefit ratio. Nutty, I know.

  7. Chad Estes

    Wouldn’t Induced Demand assume there are multiple routes to a destination? In your NYC example you can take rail, highway, another highway, road. In Austin, there’s really only Mopac and I-35.

    Basically, increasing the capacity of Mopac and I-35 wouldn’t cause an influx of people to use them rather than their original routes because there were no other routes to begin with. Those two roads are basically it. Increasing capacity on those roads would at least reduce the length of time that ‘rush hour’ happens during the day, I would think.

    It’s a shame that I can’t take the rail instead of the highway. …or any other route, really.

  8. Dustin

    Another thing you failed to address: NYC has a viable public transit system. Austin does not. Buses do not run on time and have limited access. Trains are even more limited. Look at cities such as San Jose and see what they have done. We could learn a lot from these cities.

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  10. Marshall

    You know, I’d agree with you completely if you changed “no more roads” to “no more highways.” Austin’s problem as I can see it is that there are tons of high capacity highways with high speed limits and little pedestrian capacity but way too few surface roads. There are neighborhoods all over Austin in which the infrastructure requires that you get in a car for every trip out of the house. We don’t need another I-35, I’d argue, but we need a lot more Duval Rds: lower capacity, pedestrian-friendly surface streets that pass through both residential and commercial areas.

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