Recently, I read an email newsletter arguing that cities really can build their way out of congestion, because the regions that have actually reduced congestion have built so many roads that the increased road mileage actually exceeded the increase in vehicle miles traveled.

I have no doubt that this proposition is true for the past few years, but only because over the past decade or so, congestion decreased in most cities, regardless of their policies. According to the Texas Transportation Institute (TTI), the number of hours per driver lost per congestion in the 101 largest urbanized areas decreased from 52 in 2005 (its all-time high) to 43 in 2011—the same level as in 1996. (All TTI data discussed here are available at an Excel spreadsheet available at this link.)

But to me, the more interesting question is the long-term trend, starting from 1982 (the first year of TTI’s statistical database). Because congestion increased almost everywhere during the 1980s and 1990s, only three regions are less congested (as measured by hours lost per driver) than 30 years ago: Anchorage, Alaska, Indio-Palm Springs, California, and Lancaster, California.

In Anchorage, the number of freeway lane miles did not keep up with vehicle miles traveled (VMT): VMT increased by just over 70 percent (from 800,000 to 1.38 million) and lane-miles increased by just over 50 percent (from 125 to 190). However, arterial lane-miles did grow more rapidly, increasing by 28 percent (from 300 to 386) while arterial VMT increased by less than 20 percent.

In Indio, freeway miles increased by 144 percent (from 45 miles to 110) while VMT again increased somewhat more rapidly, by 171 percent (from 390,000 to 1.058 million). Arterial streets increased by 136 percent (from 345 miles to 817), while arterial street VMT increased by 179 percent (from 1.6 million to 4.473 million). So even for arterial streets, VMT actually increased more rapidly than road mileage. Continue reading →