“Building bigger roads actually makes traffic worse,” asserts Wired magazine. “The reason you’re stuck in traffic isn’t all these jerks around you who don’t know how to drive,” says writer Adam Mann; “it’s just the road that you’re all driving on.” If only we had fewer roads, he implies, we would have less congestion. This “roads-induce-demand” claim is as wrong as Wired‘s previous claim that Tennessee fiscal conservatives were increasing Nashville congestion by banning bus-rapid transit, when actually they were preventing congestion by banning dedicated bus lanes.
In support of the induced-demand claim, Mann cites research by economists Matthew Turner of the University of Toronto and Gilles Duranton of the University of Pennsylvania. “We found that there’s this perfect one-to-one relationship,” Mann quotes Turner as saying. Mann describes this relationship as, “If a city had increased its road capacity by 10 percent between 1980 and 1990, then the amount of driving in that city went up by 10 percent. If the amount of roads in the same city then went up by 11 percent between 1990 and 2000, the total number of miles driven also went up by 11 percent. It’s like the two figures were moving in perfect lockstep, changing at the same exact rate.” If this were true, then building more roads doesn’t make traffic worse, as the Wired headline claims; it just won’t make it any better.
However, this is simply not true. Nor is it what Duranton & Turner’s paper actually said. The paper compared daily kilometers of interstate highway driving with lane kilometers of interstates in the urbanized portions of 228 metropolitan areas. In the average metropolitan area, it found that between 1983 and 1993 lane miles grew by 32 percent while driving grew by 77 percent. Between 1993 and 2003, lane miles grew by 18 percent, and driving grew by 46 percent.
That’s hardly a “perfect one-to-one relationship.”
Few problems are as costly as traffic congestion. According to the Texas Transportation Institute, it costs commuters more than $100 billion per year. Studies in a number of cities suggest that costs to businesses are roughly equal to that, for a total annual cost of around $200 billion. Yet it is hard to persuade people that the only effective solution–variable tolls aimed at preventing ttraffic from reaching congested levels–should be implemented.
Atlantic Cities may have found the literal poster-children that could do it: premature babies. According to research reported in an article by Brooklyn resident Sarah Goodyear, tolls that reduce congestion also reduce air pollution (a fact the Antiplanner has often pointed out) which in turn reduces the number of babies born prematurely.
Because a quarter of all U.S. housing is located near congested highways, ending that congestion and the resulting pollution “could reduce preterm births by as many as 8,600 annually, for a cost savings of at least $444 million per year,” estimates a MacArthur Foundation policy brief. Now, $444 million is only 0.2 percent of the total cost of congestion, but it might be the 0.2 percent that will get people to accept that they should pay more to use roads during peak periods of the day just as they pay more to use airlines, hotels, telephones, and other services during peak periods–and that would benefit everyone except for the people who enjoy watching other people sit in traffic.
“Who needs traffic lights?” is the name of the YouTube video shown below. It shows an intersection in Ethiopia in which some fourteen lanes of traffic cross six more, with pedestrians wandering amidst vehicles turning right, left, and going straight unhampered by signals, signs, or seemingly any conventions other than to drive on the right.
This video seems to support proposals by many urban planners that streets would be safer if there were fewer, not more, signals and signs. At the extreme is the late Hans Monderman, a Dutch traffic planner who advocated getting rid of street signs, signals, and crosswalks.
Portland traffic is “stressful and unpredictable,” according to one of the co-authors of the Texas Transportation Institute’s urban mobility report. In fact, by some measures, Portland has the sixth-most-congested freeways in the nation, after DC, New York, Los Angeles, Bridgeport, and (strangely) Provo-Orem.
There are other measures by which Portland isn’t quite so bad, though overall Portland ranks 17th even though it is the 23rd largest urban area. The significance of the freeway number is that it is based on actual measurements of traffic by Inrix, while most of the other measures are calculated based on estimates of miles of driving and lane miles of roads. The Antiplanner has never trusted these calculations because a lane mile of highway built in 2000 has a far greater capacity to move traffic than one built in 1950. Thus, the measure that ranks Portland sixth-worst is probably one of the most reliable in the report.
Portlandia supporters, of course, attempt to double-talk their way out of this. The mobility report, says one, “ignores differences in trip distances among metro areas and how trip distances have changed over time.” The Texas people disagree, saying they do take distances into account. Moreover, a look at census data reveal that the average Portland commuter takes 24.2 minutes to get to work, which about the same as in other urban areas of similar size (Minneapolis is 23.4 minutes; Denver is 25.7; St. Louis is 23.6; Cincinnati is 22.8; San Antonio 23.8). Since census data also show that 85 percent of Portland-area commuters still take autos to work, Portland’s investments in transit and bike paths have, at best, merely nibbled at the edges of the problem.
The Texas Transportation Institute has released its annual urban mobility report, and Washington, DC once again takes the crown of wasting the most time and fuel per commuter. Though the urban mobility report makes some questionable claims about the congestion relief provided by urban transit, not even DC’s expensive Metro rail system has kept traffic from costing the average auto commuter $1,400 a year in wasted time and fuel.
Of course, one reason DC is number one in congestion is that, with the growth of government during the recent recession, it has enjoyed far more job growth than most other major urban areas. Yet, if rail transit really were such a good way to relieve congestion, it should have been able to absorb that growth.
Instead, the rail system operated by the Washington Metropolitan Area Transit Authority (WMATA) is actually losing capacity as maintenance shortfalls force the agency to run smaller trains and those trains become less reliable. Last summer, when passengers on the Green line were stranded and had to walk along the rail line in the summer heat, WMATA promised that the agency would improve its safety procedures and keep people better informed.
Last month, the National Transportation Safety Board listed mandatory adaptive cruise control and other collision-avoidance technologies as one of its ten most wanted safety improvements in 2013. Such a mandate, the NTSB estimates, could reduce highway fatalities by 50 percent.
Honda’s illustration of how adaptive cruise control can reduce congestion. In normal traffic, when a lead vehicle slows down, everyone else must slow and usually slows a little more for safety reasons, thus leading to stop-and-go traffic. If one vehicle in the middle of a platoon has adaptive cruise control, it won’t slow as much, interrupting the pulse of congestion.
Research has shown that adaptive cruise control can also significantly reduce congestion by interrupting the “pulses” of slow traffic that takes place when someone hits the brakes, even if only briefly, on a crowded highway. The research suggests congestion will significantly decline if only 20 to 25 percent of vehicles on the road are using adaptive cruise control. tHowever, researchers fret that too few vehicles are being made with adaptive cruise control to have an impact on congestion in the near future.
The Texas Transportation Institute recently published its latest urban mobility report, rating the amount of congestion in each of more than 100 urbanized areas. The report also estimates total congestion costs in 439 urbanized areas.
The Antiplanner has taken previous reports with a grain of salt because congestion estimates were based on formulas rather than on actual measurements of traffic delays. This report, for the first time, incorporates information from actual traffic speeds. The authors say they have backtracked this new methodology to the year 2000, but data before then (which go back to 1982) rely on the old methods. There does not appear to be a significant discontinuity between 1999 and 2000, which suggests either that the old methodology wasn’t too bad or the new data don’t play a huge role in the calculations.