Harvard Study Finds Separated Bike Lanes Safer

Injury Prevemtion Screenshot

A study conducted by researchers at Harvard’s School for Public Health and published last month in the journal Injury Prevention, found that riding on separated “cycle tracks” (separated bike lanes along roads) is safer than riding on streets without bicycle infrastructure. From the abstract:

Most individuals prefer bicycling separated from motor traffic. However, cycle tracks (physically separated bicycle-exclusive paths along roads, as found in The Netherlands) are discouraged in the USA by engineering guidance that suggests that facilities such as cycle tracks are more dangerous than the street. The objective of this study conducted in Montreal (with a longstanding network of cycle tracks) was to compare bicyclist injury rates on cycle tracks versus in the street. For six cycle tracks and comparable reference streets, vehicle/bicycle crashes and health record injury counts were obtained and use counts conducted. The relative risk (RR) of injury on cycle tracks, compared with reference streets, was determined. Overall, 2.5 times as many cyclists rode on cycle tracks compared with reference streets and there were 8.5 injuries and 10.5 crashes per million bicycle-kilometres. The RR of injury on cycle tracks was 0.72 (95% CI 0.60 to 0.85) compared with bicycling in reference streets. These data suggest that the injury risk of bicycling on cycle tracks is less than bicycling in streets. The construction of cycle tracks should not be discouraged.

Read the study

14 Responses to “Harvard Study Finds Separated Bike Lanes Safer”

  • Rudy Faust says:

    Thank you for posting, Alan. Especially important in light of events in NYC, where personal politics trump safety and smart planning:

  • Alan Barnard says:

    Good article Rudy – thanks for the link. You’re absolutely right about personal politics trumping safety and smart planning in NYC these days.


  • Jay (Epstein) in Tel Aviv says:

    I’ve never been to Montreal.

    Tel Aviv has installed quite a number of bike lanes in the last few years. They are generally so poorly planned that I’m not sure they make my ride easier or safer.

    From what I read I believe that this is the case in many places.

    Governments want to be seen as pro-bicycle but are not willing to take space away from cars. This leads to bike lanes on sidewalks, or between parked cars and the curb, with no thought at all to interactions between cars and bikes at corners.

    Stay alert folks – it’s a mess out there.

  • Andrew Leinonen says:

    Isn’t this a pretty obvious conclusion? Physical separation will obviously lead to fewer physical…interactions, shall we say.

    Clearly the (lack of) widespread adoption of separated lanes has nothing to do with safety and everything to do with money and political will.

  • pete rosenfeld says:

    I looked at this study in some depth and I don’t think the streets they used as a reference are really comparable with the streets that got the 2-directional sidepaths. Look for yourself with google map streetview. They chose the reference streets because they ran parallel to the side-pathed streets, not because they were truely comparible. In any case, using a couple of streets for a baseline is not enough to get a statistically significant reference.

    A much better way to do this is to measure the “before and after” accidents rates – measure before the path goes in and then again after it goes in. Copenhagen did a very good “before and after” study on a large number of streets and got VERY different results.

  • JWLane says:

    Non-separated bike lanes: In Tennessee (where motorists have to practically be stunt driving to get a moving violation), I have to be constantly defensive to stay alive. The bike lanes I use are taken over by Greyhound buses, dump trucks, SUV’s, everything. The spit second their tires veer to the edge of the lane, I jam the brakes to keep from being crushed. Sometimes they take the bike lane for turning. Sometimes they’re texting and using the bike lane as a low-attention-to-driving buffer. The ‘very’ consistent law enforcement response is that it’s my problem for being out there on a bike to begin with. From what I read, this last bit rings familiar for most of the US and Canada.

    I like some of the bike lanes in Paris (France, not Kentucky). There is a thick, wheel stopping curb that separates bike lanes from motor traffic.

  • Bob P. says:

    The only areas where a separate bike lane should be considered, is where the speed differential between the cars and the bikes is great. I’d rather be on the streets with the cars when the speed is <35 mph. Most streets with a higher speed limit are wider, so the safety issue is mitigated by the rider being able to stay to the right, without impeding automobile flow. With this in mind, few roads need a separate bike lane.

    What we really need is education for all road users. We license people to drive a car when they are teenagers, and in spite of law changes, demographic changes, and increased road usage, there is no requirement for continuing education in order to keep a drivers license. Most of my issues with drivers are with older rude people, who mistakenly think I should get to the curb when they approach from behind.

  • pete rosenfeld says:

    I disagree that side paths are better on streets with a large speed differential.

    My ilk has always argued that, in urban environments, the dangerous spots are intersections, both major ones and minor ones ( like driveways). Older studies show most accidents between bikes and cars happening where their paths cross and not when they are both traveling in the same direction. So we generally say side paths ( separated from the road by a barrier or just some space) are a bad idea if they cross many intersections because they only protect the bicyclist from same direction traffic, which is not a significant risk, while complicating the intersections and making that already significant risk worst. Most importantly, by removing the bicycle away from the main flow of traffic automobike drivers are less likely to notice them at intersections, increasing the risk of right hooks and left hooks.

    I would say it is not the speed differential that determines if side paths are OK, but the number of intersection crossings. If there are few, like on a bridge or along a natural barrier like a river, they may be OK and even have protective value.

    The Harvard study refenced here does not agree with those conslusions. That’s why it got my attention. They studied bi-directional sidepaths, which from an intersection point-of-view are THE worst type of facility. I would have been impressed if it was shown that these sidepath do not significantly increase accidents. A number of studies have shown this for bike lanes and side paths that have few intersections. Instead, they find that these facilities actual REDUCE accidents, something I have NEVER seen in any well-designed study.

  • Michael Cullen says:

    Thanks for this post! I’m in the middle of a graduate research paper on bicycle infrastructure, and this will be helpful.

  • Maurice Loridans says:

    I like both Bob P and Pete’s comments above and think they can be harmonized. Arterial and rural roads are both higher speed and present fewer intersections than urban grid streets. Infrastructure improvements would be much more effective in these areas than in the sub 35 mph urban streets.

    This was discussed and developed at length here: http://www.bikeforums.net/showthread.php/716988-cycletrack-buffered-lane-bicycling-facilities-report-from-Portland-State-U

    See comments number 3,5,17,19 in that thread.

  • Hans van Tol says:

    This study makes reference to bike paths/cycling tracks in the Netherlands. And it is true that the Netherlands have a large number of separated bicycle facilities. However, this really should be put into some kind of context. The Netherlands has a strict separation between urban and rural space, with maximum speeds within the urban area 30 mph or lower and outside the urban area usually 55 mph. There are many separated 2-way bicycle paths outside the urban area (and if a such bikepath exists, bicycles are not allowed on the road)), but inside the urban area they are rather rare. Sometimes one-way bicycle tracks are present, but otherwise bikelanes or no special facilities other than bike-boxes at traffic lights are the norm. Simply put, if there are few intersections, bikepaths can be a solution. If there are many intersections and driveways, they should be avoided.

  • Friday Film Fun: Bikeshare changing the face of cycling in Barcelona | Austin On Two Wheels says:

    […] is key. As the 50% reduction in accidents in New York City after bike facilities were added and recent research shows not only does this help sell cycling as a valued, legitimate form of transport, it also is […]

  • Adriana says:

    This link is to a report from the City of Montreal showing schemetics of it’s physically separated bike lane system, compared to conventional bike lanes.

    see page 44 and the appendices:

    photos of montreal’s separated bike lanes. Note that in more residential area, the bi-directional bike lane is buffered by parked cars… so bikes travel between the sidewalk and parked cars, not on the road-side of the parked cars, next to traffic.

  • Adriana says:

    forgot the photo link: http://www.flickr.com/photos/adrimcm/sets/72157622923072021/with/4173081097/

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