The University of British Columbia cycling safety research group Cycling in Cities presented the Velo-City 2012 conference with some fascinating studies on the relative safety of urban cycling infrastructure in Canada. Their findings could be extremely useful as the city updates the Bicycle Master Plan and attempts to take the first steps in creating a network of neighborhood greenways.
One big—and somewhat surprising—find is that traffic circles scored very poorly. Seattle has invested heavily in residential street traffic circles, which are proven to reduce traffic collisions and slow motor vehicle speeds without the negative effects of having too many stop signs (the more seemingly pointless stop signs you have in a traffic system, the more people tend to roll or ignore all stop signs, which is bad).
However, while traffic circles might work well at reducing car collisions, the BC study suggests that people biking do not fare as well. Traffic circles have been at the heart of the debate between SDOT and many neighborhood greenway advocates, who want to see stop signs for residential streets that cross a neighborhood greenway. SDOT has maintained that traffic circles are an acceptable treatment and do not want to add the signs. So this study could give greenway advocates a push in making their case.
The best scoring factor for safe neighborhood streets in the study is traffic diversion (1/20 the risk compared to no infrastructure). Fewer cars means better safety for people cycling, so constructing barriers to reduce through traffic makes the street safer. All points on the street remain accessible to people driving, but anyone traveling more than a couple blocks should be required to take other streets (preferably, a nearby arterial street).
These findings suggest the city may have missed some opportunities with the Wallingford neighborhood greenway on N 44th/43rd Streets. All intersections along the route are controlled by traffic circles (preexisting) without stop signs, and the city scaled-back a traffic diverting crossing at Stone Way to allow motor vehicle turns and through traffic movements.
This isn’t to say the Wallingford Greenway is a failure or that SDOT’s trust is traffic circles is misguided. Our neighborhood streets are very skinny, and car speeds are very low (another very key factor in cycling safety). It’s not clear how our street conditions compare to those studied. But we should be looking for ways to make each neighborhood greenway we create better than the ones before it. Projects due to be completed this summer include neighborhood greenways on Beacon Hill, NE Seattle and West Seattle.
Other findings in the study suggest that cycle tracks are, indeed, extremely safe (1/20 the risk compared to no infrastructure). We should be installing them as our go-to piece of infrastructure on high traffic streets. Bike lanes are slightly safer than nothing, and sharrows actually scored worse than no infrastructure at all.
As Portland planner Roger Geller reportedly said during a Velo-City presentation, “Just use the hammer.” Protected bike facilities are clearly the best, and they should be used in nearly all arterial street situations. This should be a key tenet in the new Bicycle Master Plan.
Perceived vs Observed Risk
Cycling in Cities also presented on the relationship between perceived risk and observed risk for cycling facilities. Their findings suggested that people have a pretty good idea of which facilities are dangerous.
However, people studied suggested that they felt cycle tracks are more dangerous than they actually are. They also thought multi-use trails (where people biking mix with people walking, roller blading, etc) are safer than they actually are.