Originally Posted by
randya
From the peer-reviewed literature; just published in the Environmental Health Journal by five researchers from the University of British Columbia:
Methods
We reviewed studies of the impact of transportation infrastructure on bicyclist safety. The results were tabulated within two categories of infrastructure, namely that at intersections (e.g. roundabouts, traffic lights) or between intersections on “straightaways” (e.g. bike lanes or paths). To assess safety, studies examining the following outcomes were included: injuries; injury severity; and crashes (collisions and/or falls).
Results
The literature to date on transportation infrastructure and cyclist safety is limited by the incomplete range of facilities studied and difficulties in controlling for exposure to risk. However, evidence from the 23 papers reviewed (eight that examined intersections and 15 that examined straightaways) suggests that infrastructure influences injury and crash risk. Intersection studies focused mainly on roundabouts. They found that multi-lane roundabouts can significantly increase risk to bicyclists unless a separated cycle track is included in the design. Studies of straightaways grouped facilities into few categories, such that facilities with potentially different risks may have been classified within a single category.
Results to date suggest that sidewalks and multi-use trails pose the highest risk, major roads are more hazardous than minor roads, and the presence of bicycle facilities (e.g. on-road bike routes, on-road marked bike lanes, and off-road bike paths) was associated with the lowest risk.
Conclusions
Evidence is beginning to accumulate that purpose-built bicycle-specific facilities reduce crashes and injuries among cyclists, providing the basis for initial transportation engineering guidelines for cyclist safety. Street lighting, paved surfaces, and low-angled grades are additional factors that appear to improve cyclist safety. Future research examining a greater variety of infrastructure would allow development of more detailed guidelines.
More selected quotes:
Bicyclists are vulnerable because they must frequently share the same infrastructure with motorized vehicles, and yet bicycles offer their users no physical protection in the event of a crash. In addition, the mass of a typical automobile is at least an order of magnitude greater than a bicycle plus its rider, and motorized vehicles have top speeds that are considerably faster than bicycles. As a result, bicycle riders who are involved in a crash are exposed to a much higher risk of injury compared to motor vehicle users (with the exception of motorcycle riders).
In this paper we review the evidence on how different types of transportation infrastructure affect bicyclists’ safety. This paper is organized as follows: first we provide an overview of bicycling safety and ridership. Next we offer definitions of, and alternative terminology for, the transportation infrastructure used by cyclists that might be expected to influence their safety (Table 1). We describe our literature search methodology and the inclusion and exclusion criteria, and present the results of the search in two detailed tables. Table 2 describes studies that assess the safety of intersections for cyclists, and Table 3 describes studies related to straightaways (i.e. roads, lanes, paths). We conclude by discussing the findings of this review, critiquing the methodological approaches used, and offering recommendations for future research.
abstract
provisional full report (pdf)
one thing this report makes clear to me is that you can't just lump traditional multiuse paths in with bicycle-specific cycle tracks or bike lanes when evaluating facility safety.
I am not surprised that this has shown up in this discussion, for I have already reviewed it on my website at:
http://johnforester.com/Articles/Saf...e%20Impact.pdf
The plain fact is that because these health professionals knew nothing about bicycle transportation, they failed to recognize the errors in these studies, or, more often, in the interpretation given to the studies, problems that we bicycle transportation engineers had identified long ago. The result of correcting these errors is that the published literature makes no demonstration that bikeways reduce car-bike collisions. Some errors: The CPSC study gives the average speed of cyclists as 1.26 mph. The Kaplan study is quoted as demonstrating a lower crash rate on bike lanes when all of its data apply to bike routes, because in 1975 there were very few bike lanes in America, but many more miles of bike route. The Wachtel study is quoted as showing that right-way sidewalk cycling is not much more dangerous than roadway cycling through the same intersections, despite Wachtel's note that this is a statistical anomaly rather than accurate information. And the reviewers equate all roadway cycling with vehicular cycling.
It's not only garbage in, garbarge out, but decay into garbage of originally reasonable information.
I sent my review to the editor, who replied that I should send a concise letter instead, which I did. But they won't publish even six paragraphs without payment of $1350. Think of that: their journal publishes erroneous information, and they demand money for the corrections.
We have had much discussion of the absence of peer review in our subject. Now look at the errors that "peer" review let through. As I remarked to one committee of high review in the transportation sciences, I would be only too pleased if papers were reviewed by those who were my peers, instead of the ill-informed people who were assigned to the task.