Does cycling infrastructure reduce serious accidents?
A new Canadian study confirms what cyclists intuitively know: providing quality cycling infrastructure reduces the risk of accidents and serious injuries
In the latest issue of the American Journal of Public Health, a team led by Professor Kay Teschke from the School of Population and Public Health at the University of British Columbia, reports on a study examining injury risk associated with 14 types of cycling route.
They interviewed 690 adult cyclists in Vancouver and Toronto who’d been injured seriously enough while riding to be admitted to hospital within 24 hours (the severity of the injuries is not reported). Two thirds of those eligible for the study agreed to participate.
The 14 route types were categorised in four groups: major streets with parked cars; major streets without parked cars; local streets; and off-street routes.
The three on-street groups were further subdivided to account for various types of lane markings and traffic calming. The off-street routes were refined to account for variables like sharing with pedestrians and type of pavement.
The researchers found a third of accidents involve a direct collision with a motor vehicle (although another 14% of injuries are sustained in avoiding a vehicle). Most of those injured are regular cyclists, male, younger than 40 and well educated.
Accidents are distributed more or less evenly across the four main road types. However more than half of all injuries are sustained on streets with no cycling infrastructure (i.e. no works, no signs, no on-street markings).
Compared to major streets with parked cars and no bicycle infrastructure (the reference type), segregated on-road bicycle tracks have about one ninth the risk of serious injury. Marked bike lanes on major streets with no parked cars have nearly half the risk, as do dedicated off-street bike paths.
However off-road paths shared with pedestrians have about three quarters of the risk of the reference type. The authors don’t say but I expect this reflects conflict with other users.
The study also found that aside from cycling infrastructure, other route characteristics are also associated with risk reductions: quiet streets (i.e. local streets); and no car parking on major streets.
On the other hand, downhill slopes, tram tracks and construction work are much riskier than the reference route type (more than three times in the case of tram tracks).
The study also compared the risk associated with the route types against those route characteristics cyclist’s in general say they prefer. As the exhibit shows, there’s a high correspondence between these two variables. Cyclists intuitively know what’s safer.
Many route types with positive preference ratings were also among the safest: cycle tracks; local streets; bike only paths; and major streets with bikes lanes and no parked cars. These provide a range of options with potential to both lower injury rates and increase cycling. This in turn may create a positive feedback cycle because increased ridership has been associated with increased safety.
Teschke et al’s findings are consistent with those of Buehler and Pucher’s study of 90 US cities. As I’ve discussed before, they found the supply of bike lanes and paths per capita is a statistically significant predictor of bike commuting.
Cities with a greater supply of bike paths and lanes have significantly higher bike commute rates. They found this to be true even after controlling for land use, climate, socioeconomic factors, gasoline prices, public transport supply, and cycling safety.
The link between safety – whether real or perceived – and cycling for transport purposes is compelling. Better infrastructure encourages more cycling and lowers injury costs.