A transportation paradigm shift that we need is moving too slowly

By Chris McCahill 

Our transportation system in the U.S. is built and maintained largely on basic principles that are now a century in the making. The first principle is that cities and metropolitan areas will continue growing outward. Second, almost everybody will drive. And third, by adding road capacity, we can prevent the system from breaking down. As a result, commute times have risen by more than 20% over the last 50 years, and only the pandemic has offered any relief from traffic congestion. 

Trends in average commute times and traffic delay in the U.S. See technical note below for sources.

Some forward-looking researchers, planners, and engineers have long argued that instead of focusing on how fast or slow vehicles are moving, we should focus on how easy it is for people to get where they need to go. That often means traveling shorter distances at slower speeds and by modes other than driving. 

This concept—often called accessibility or access to opportunities—dates to a research paper from the 1950s. Related research has taken off since the early 2000s and there are now several books on the subject. SSTI also produced a guide to measuring accessibility in 2021 and hosted a four-part webinar series last year featuring practitioners from across the U.S.  

A new study now offers a fresh perspective on the current state of practice and some critical challenges to moving toward accessibility as an industry. The study was led by Dana Rowangould at the University of Vermont, who discussed the topic in a recent SSTI webinar, and Alex Karner at UT Austin. 

For this study, the researchers surveyed 42 practitioners from 31 different organizations, including state DOTs, metropolitan planning organizations, transit agencies, and private companies. Despite identifying some common challenges related to staff capacity, technical limitations, and data limitations, participants consistently reinforced the idea that accessibility measures are extremely useful and critical for tying transportation and land use together.  

The study points to opportunities for leveraging existing data and incorporating accessibility analysis into things like scenario planning and project prioritization—especially where transit, biking, and walking are concerned. 

However, it also points to a critical need for more federal support. The study notes: 

There are federal goals to “reduce congestion” but none relating to “increasing accessibility,” so agencies seeking to incorporate accessibility analyses must go above and beyond federal reporting requirements to do so. Many users and nonusers kept track of several other performance measures in accordance with federal MAP-21 reporting requirements but noted difficulty obtaining the resources or permission to compute accessibility measures above and beyond these requirements. Ultimately accessibility is not a required performance measure, so it is difficult for some to direct resources toward it or view it as fundamental or distinct from other performance measures.

A new Transportation Access Pilot Program, announced as part of the Bipartisan Infrastructure Law could be an important first step, even if it is a small one. Anyone anticipating the program might have been disappointed to learn that it offers no new funding or access to data. But it will support a peer learning community that could advance the practice considerably and give federal officials the information they need to formalize accessibility analysis in future efforts. Without a coordinated national movement toward measuring accessibility, it will continue to be an ad hoc process and, more importantly, it will remain a low priority, compared to the status quo. 

Letters of interest for the pilot are due by June 7. State DOTs and regional planning agencies are eligible. Priority will go to those who already have some experience in accessibility analysis.

Technical notes:

  1. Average commute times are derived from the decennial Census for 1980 to 2010, and from the 2022 five-year American Community Survey.
  2. Average annual traffic delay is derived from Table 1-69 in the Bureau of Transportation Statistics’ annual report, representing the 494 largest urban areas.

Photo Credit: Adrian Williams via Unsplash, unmodified. License.