I-35: Three-Hour “Rush Hours”

Movability Austin usually stays away from long-term planning proposals that don’t help commuters now or in the near future, but this topic is just too big to ignore. Whether it’s surveys, talk radio, or social media, the biggest complaint about transportation in Austin is traffic – particularly traffic on I-35. The buzz has only increased lately with ideas like Mobility 35’s proposed improvements, the push to “cut and cap” portions of I-35, and a national NPR story about just how bad Austin’s traffic is.


The most interesting new information about I-35 comes from recent traffic modeling. That modeling shows that most traffic on I-35 is local. It also shows that the solution most people ask for – to build more lanes – will not do much to improve traffic flow if we don’t also change some basic characteristics of our travel habits.

If current travel patterns and trends are maintained, we could build every single project identified in our long-range regional transportation plan and the average travel time would still reach 190 minutes in the morning and roughly the same in the evening. That’s six hours stuck in traffic every day! According to modeling done by the Texas Transportation Institute (TTI), even with $1 billion in spending on top of projects already in the planning stages like managed lanes, we would still have five and a half hours per day of traffic moving at 10mph or less.

Arguably few people are willing to make three-hour commutes each way, and that is the real problem: we do not want people leaving the region as they seek relief. We as a region need to emphasize transportation changes that can make a difference on I-35. That big difference happens when people shift “how” and “when” they travel. Increased transit use, staggered work hours, carpooling, telecommuting, or even choosing to live closer to work can make a big impact on traffic.

In fact the changes in travel habits people are likely to make also have the biggest impact on I-35 traffic. In the same modeling, TTI ran a scenario to see “what happens if we reduce the number of cars on I-35 by 25 percent?” If traffic could be reduced by that amount, TTI found that from today through 2035, traffic would not slow below 35 mph during rush hour, and would flow freely most days and evenings.

This isn’t an argument for the “if we don’t build it, they won’t come” mindset. Rather, we think this information calls into question the false paradox that we must either build roads for cars or not build anything. Transportation best practices are beginning to recognize that rural, suburban, and urban areas need very different travel options, and are beginning to ask the right questions to plan tailored transportation projects.

In his new publication, “Smart Congestion Relief,” Todd Littman of the Victoria Transport Policy Institute says “Transportation system efficiency, economic productivity, and community livability tend to increase if automobile travel is minimized…This doesn’t require eliminating automobile travel entirely; even in large cities a portion of trips are efficiently made by car. However, as cities become larger and denser, automobile mode share should decline.”

Our challenge for downtown Austin, and the entire region, is that our community has not even begun an earnest discussion about how much “driving alone” is too much for our transportation system. While organizations like Project Connect, Mobility35, MoPacExpress, and CAMPO are working on long range solutions,  we as a region can’t afford to wait to start making some changes. Contact your favorite transportation agency and ask if their plans manage to reduce “drive alone” traffic and give commuters viable choices to avoid even longer rush hours of commuting. Protect our quality of life even with the fast-paced growth we experience each decade.

Comments are closed.