Data from Teschke et al., Route Infrastructure and the Risk of Injuries to Bicyclists, Table 4, descriptions modified, *P less than .05
The Atlantic's Cities blog has a decent summary of a recent paper aimed at determining the impact of various kinds of cycling infrastructure on injury rates. Among the study's conclusion is that bike lanes significantly reduce the rate at which cyclists are injured.
Terminology & Denver's Paths
At the outset, I should note that study's terminology doesn't match up well with how we in Denver refer to things. According to the study's definitions, the Cherry Creek and Platte Greenways are "multiuse" paths ("meant for nonmotorized use by pedestrians, cyclists, skaters and others, either alongside city streets or away from city streets") not "bike paths."
I'm not sure how the study would classify Denver's designated sidewalk/bike routes. Those monstrosities fit both the definitions of sidewalk ("paved path meant for pedestrian use, either alongside city streets or away from streets") and multiuse path. (As far as I know, we don't have any "bicycle-only paths" in Denver.)
Multi-Use Paths Are (Relatively) Unsafe
The study's results are interesting for several reasons. First, in terms of safety, multi-use paths are less safe than everything except sidewalks and major streets with parked cars and no bike infrastructure.
That probably surprises a lot of planners. Multi-use paths are assumed to be the safest place for cyclists to be.
If the results apply to Denver, Denver has built (and designated) a lot of infrastructure that is less safe to use than simply riding on a major street that doesn't have parking. In particular, where Denver has designated sidewalks as bikeways it has created conditions that are about as unsafe as they can be for cycling.
Parking Poses Problems
Another interesting thing is just how much difference street parking makes. Eliminating parking makes even major streets safer than adding a bike lane or sharrows would. (The risk for major streets with no parking and no infrastructure are not statistically significant.)
If cyclist safety is an issue, planners should consider removing parking before considering adding cycling infrastructure. (Anyone who has worked on these issues in Denver knows that's wishful thinking. A bike planner once told me -- sarcastically -- that City Council, given a choice between a few dead cyclists and the calls triggered by eliminating a few parking places, would choose dead cyclists every time. He might have been sarcastic, but I think he was right.)
What's Hurting Us
Finally, how cyclists were injured surprised me. Only about a third of cyclist injuries were caused by collisions with motor vehicles. About a quarter were caused by collisions with things like train tracks, potholes, or rocks. Collisions with animals, other cyclists, and pedestrians accounted for only about 7% of the injuries. Looks as if keeping streets maintained on bike routes would help a great deal. Drivers would appreciate it, too.