Cycle track safety remains unproven.

Lusk et al. claim that American Association of State Highway and Transportation Officials (AASHTO) guidelines discourage " physically separated and bicycle-exclusive paths adjacent to sidewalks. " 1 In fact, these guidelines prohibit bicycle lanes on the roadway separated from travel lanes by parked cars or a raised barrier. They permit bike paths adjacent to the roadway where there is " minimal cross flow by motor vehicles. " 2 The facilities in the authors' sample that clearly contradict these AASHTO guidelines are First Avenue North in Minneapolis, Min-nesota, and First, Second, Eighth, and Ninth Avenues in New York City. Using the authors' figures, the bicycle crash rate for these facilities averages 7.0 per 10 6 kilometers traveled compared with only 0.6 per 10 6 kilometers for the remainder of the authors' sample. An explanation for the difference is that the former group averages 11.3 intersections per kilometer whereas the latter averages only 1.7 (Table 1). Lusk et al. claim that the crash rate for their sample " is low relative to reported crash rates on roadways in the United States and Canada. " However, 3 of the 4 comparison rates they cite are based on self-reports of all collisions for specific populations (bicycle messengers in Boston, MA; bicycle commuters in Toronto or Ottawa), and not on police reports of car-bicycle collisions for all bicyclists—which makes them completely inappropriate to use as a benchmark. 3-5 The 2009 National Household Transportation Survey estimates 14.413 10 6 annual kilometers of bicycle travel in the United States. 6 Dividing by the 51 000 estimated police-reported bicyclist injuries in 2009 provides a national rate of 3.5 bicycle crashes per 10 6 kilometers. 7 The facilities that are expressly prohibited by the AASHTO guidelines have a crash rate that is on average twice as high as the national average. It is premature to say this work provides additional evidence that urban cycle tracks increase bicyclist injuries attributable to intersection risk 8-10 because the authors' method does not account for confounders such as traffic speed and volume. But it is safe to conclude that this article has produced no evidence to support its claim that " bicycling on cycle tracks is safer than bicycling on roads. " j clicking the " Reprints " link. safety on bicycle paths—results from a new large scale Danish study. 2008. Letters to the editor referring to a recent Journal article are encouraged …