Focus on relieving traffic congestion is wrongheaded, says CEOs for Cities

What Americans have been told about congested commuting trips for the past 26 years is misleading, says a new study from the business-oriented organization CEOs for Cities.

Since 1984, the Texas Transportation Institute has produced a total of 19 Urban Mobility Reports, which measure road congestion in America’s large metropolitan areas and — whether purposely or not — help build a case for road expansion.

CEOs for Cities, in a newly released analysis called “Driven Apart,” available here, accuses the Urban Mobility Report (UMR) of being based on flawed methods, with the result that “it does not accurately estimate travel speeds, it exaggerates travel delays, and it overestimates the fuel consumption associated with urban travel.”

The CEOs for Cities study, prepared by Joe Cortright with financial support from the Rockefeller Foundation, takes aim at the Urban Mobility Report’s calculation of how many hours commuters spend in traffic backups and which metropolitan areas have the most burdensome trips to and from work.

“Several of the cities that UMR ranked high for congestion — including Chicago, New York, and Sacramento — have among the lowest peak period travel times,” CEOs for Cities said. Five of the regions the UMR identified as having the least severe congestion problems — Nashville, Oklahoma City, Birmingham, Richmond, and Memphis — actually have the longest commutes when measured by distance, according to Cortright. These longer distances lead to greater fuel consumption and the emission of more greenhouse gases, aggravating global warming.

The “key tool” in the Urban Mobility Report — the Travel Time Index — “actually penalizes cities that have shorter travel distances and conceals the additional burden caused by longer trips in sprawling metropolitan areas,” Cortright declared.

“According to the UMR, things are much worse in Chicago than in Charlotte,” the CEOs report observed. The UMR says commuters in greater Chicago spend a larger proportion of their trips to and from work in congestion than do people in greater Charlotte. On the Travel Time Index — where a higher number indicates a more frustrating commute — Charlotte is rated at 1.25 while Chicago is rated at 1.43.

Cortright acknowledges that Chicagoans spend less of their total commute in free-flowing road conditions, but he points out that the total travel time for Chicagoans is 32.6 minutes, while travel time in Charlotte is 48.0 minutes. The average trip in Chicago is substantially shorter than in Charlotte —13.5 miles versus 19.0 miles.

In the view of Cortright and CEOs for Cities, the UMR leads people to draw the wrong conclusion — to think it would be desirable and feasible to eliminate highway congestion. Cortright argues that more attention should be paid to “access to destinations.” By that measure, a compact metropolitan area is better; people don’t have to go as far, burn as much fuel, or pollute as much to reach their destinations.

The UMR, by emphasizing congestion, puts its weight behind the idea that metro areas need more and bigger highways to speed the volume of vehicles, in the view of CEOs for Cities. “It rewards sprawling patterns,” Cortright said in a presentation by phone and Internet.

A model the nation could learn from is Portland, Oregon, which has shifted to more compact development and to transit, bicycling, and other means of getting around. “Average peak period travel distances in Portland have fallen one-sixth, from 19.6 miles in 1982, to 16.0 miles in 2007,” according to Driven Apart.

“As a result,” says the CEOs report, “average peak period travel times have actually gone down, from 54 minutes per day to 43 minutes per day. So rather than getting three times worse (the UMR says Portland’s Travel Time Index went from 1.07 in 1982 to 1.29 in 2007), the average peak period traveler in Portland actually experienced shorter travel times in 2007 than she did 25 years earlier.”

“Land use patterns, particularly mixed-use development, walkable and bikeable neighborhoods, higher densities, and good transit, can reduce vehicle miles traveled,” Driven Apart maintains. “Cities that pursue these strategies can reduce the total amount of time, money, and fuel their citizens spend on transportation, in effect earning a ‘green dividend’ by being able to travel shorter distances.”

Among the flaws that Cortright found in the UMR’s methods are these:

 • Differences in travel times between peak and non-peak periods are not based on travel speeds that have actually been observed. Survey data on observed speeds from INRIX, a private aggregator of travel time data from commercial vehicles, and self-reported travel times from the Census and the National Travel Survey differ from those in the Urban Mobility Report.

 • The UMR estimates of fuel consumption are based on a 29-year-old study of low-speed driving using 1973-1976 General Motors cars that averaged 13.6 miles per gallon.

 • The UMR assumes that as congestion disappears and as cars travel faster, they use fuel more efficiently. Cortright says this is false; a car traveling 60 or 70 mph may burn more fuel than one going 50 mph.

 • The UMR is oblivious to urbanism and land-use planning. “National discussions of how to make cities work better have tended to focus on making it easier for people to move, which has had the paradoxical effect of leading cities to be less dense,” Driving Apart observes. Yet a decline in density goes against the very nature of cities. Says the report: “The essential economic and social purpose of cities is bringing people together, taking advantage of opportunities for interaction and agglomeration economies.”

 Asked to respond by New Urban Network, Tim Lomax, research engineer at the Texas Transportation Institute, said his organization has for years “been very transparent about our methods and very open about problems with our data. There isn’t any reason to ambush us — we’ll tell you a lot about what’s wrong and what we’re doing to fix it.” Lomax said that “this year we are partnering with INRIX to use their data,” though he believes INRIX’s methods are far from perfect.

Lomax said the Institute uses more kinds of measures than Driven Apart indicated. He did not disagree with the contention that “sprawl is the problem,” but said “we try to measure reality … we say there are many solutions, smart growth being one.” He agreed that the Transportation Institute’s reports “are used to promote road building,” but added, “Our reports are used by everyone to prove every solution is best.” 

Norman Garrick, a transportation specialist at the University of Connecticut, said the problem is not with Travel Time Index measures in themselves. "The real problem," Garrick said, "is that currently we look at transportation through one prism — just on how well it meets our mobility need. We treat transportation as if mobility is all that matters, forgetting that transportation affects so much more."

"We don't need to get rid of TTI matrices; we just need to treat it as one of many different types of measures," Garrick believes. "We need to measure, for example, how much space is devoted to the different types of transportation systems in our cities. This is a huge issue that affects the vitality of our cities and the societal cost of transportation, but no one is systematically collecting data like this, so there is no way to really understand or account the cost. There are many other issues like this that we need much more attention to."