A new report out today from CEOs for Cities criticizes the Travel Time Index, an annual scoring of metropolitan areas and their congestion. The Index for each urban area in the US is released annually as part of the Texas Transportation Institute’s Urban Mobility Report and heavily influences decision-makers looking for solutions to traffic congestion.
For nearly three decades the Travel Time Index (TTI) has been treated as a benchmark of the state of our traffic congestion. These annual scores are widely reported, including by the US DOT, and are often used as a reason to spend more on roads. The TTI is one of the single most reported-on transportation statistics in the US.
It is also, according to a new, detailed review, wrong.
The study, titled “Driven Apart: How sprawl is lengthening our commutes and why misleading mobility measures are making things worse,” shows how the Travel Time Index actually gets daily driving backwards: cities with longer daily driving times look better that those with shorter driving times. Why? The Index leaves out something just about any traveler knows to think about: distance. By focusing only on speeds, the TTI neglects what people actually care about: how long does it take me to get there?
The report…does not downplay the negative impact that traffic congestion causes to the economy and to the quality of life across northeastern Illinois. But it points out that weak or nonexistent land-use policies in many other regions of the country, resulting in urban sprawl, carry a higher price, including longer commuting times between home and work.
[O]f big U.S. metro areas, Chicago’s commuters spend the least amount of time in their cars. That’s even though Chicago has the second-worst congestion. How can that be? Simple: shorter travel distances.
“What people really care about, and what decision makers should care about, is how much time we’re spending in our cars,” Carli Paine, TransForm’s transportation program director said in a news release. “Well designed urban areas save commuters tremendous amounts of time…”
“Driven Apart” suggests that cities focus on trip distances and total travel times—two statistics not reported in the UMR – and emphasizes that compact development and providing people with transportation alternatives are the best ways reduce traffic congestion. These methods are also the best way to invest not only in our national transportation system, but in our communities as well.