Separated bike lanes reduce injury risk significantly

Separated cycle tracks in roads carrying vehicles carried 2.5 times as many cyclists as roads without separated tracks, according to a study in Montreal by the Harvard School of Public Health.

Cyclists on separated tracks also suffered 28 per cent less injuries despite the far greater volume of traffic.

The study, lead by Dr Anne Lusk, was reported in Injury Prevention, published by the British Medical Journal.

The study was important to North America because the most influential guidelines for American traffic engineers discourage the use of cycle tracks.

“Contrary to AASHTO’s [American Association of State Highway Transportation Officials] safety cautions about road-parallel paths and its exclusion of cycle tracks, our results suggest that two-way cycle tracks on one side of the road have either lower or similar injury rates compared with bicycling in the street without bicycle provisions. This lowered risk is also in spite of the less-than-ideal design of the Montreal cycle tracks, such as lacking parking setbacks at intersections, a recommended practice.”, the study said.

And, in a section titled, “Implications for Policy,” researchers wrote:

“Public health and bicycling advocates in the USA have faced a dichotomy, believing from surveys and European experience that cycle tracks encourage more bicycling, yet being warned that they lead to higher crash and injury rates. Our results suggest that cycle tracks lessen, or at least do not increase, crash and injury rates compared with the street. The construction of cycle tracks should not be discouraged.

The separated bike lanes in Montreal have been in operation for decades

The study analysed injury and crash rates for six cycle lanes with similar street routes without separated lanes comparable for the number of cars and the speed of vehicles.

All the bike lane roads had two-way cycle traffic on one side of the road separated from motor vehicles by raised pavement, parking lanes, and/or posts. Most of the alternate streets ran parallel to the cycle track roads, and came to the same end-point intersections as the tracks.

Under the heading “Implications for Policy”, the researchers said: “Public health and bicycling advocates in the USA have faced a dichotomy, believing from surveys and European experience that cycle tracks encourage more bicycling, yet being warned that they lead to higher crash and injury rates. Our results suggest that cycle tracks lessen, or at least do not increase, crash and injury rates compared with the street. The construction of cycle tracks should not be discouraged.”

Under the heading “What is already known on this subject”, they said:

  • Individuals, in particular women, children, and seniors, prefer to bicycle separated from motor traffic.
  • Cycle tracks (physically-separated bicycle-exclusive paths along roads) exist and continue to be built in The Netherlands where 27% of all trips are by bicycle and 55% of bicycle riders are female.
  • Engineering guidance in the United States has discouraged bicycle facilities that resemble cycle tracks, including parallel sidepaths and sidewalk bikeways, suggesting that these facilities and cycle tracks are more dangerous than bicycling in the street.

The study concluded:

  • Overall, 2 ½ times as many cyclists rode on the cycle tracks compared with the reference streets.
  • There were 8.5 injuries and 10.5 crashes per million-bicycle kilometers respectively on cycle tracks compared to published injury rates ranging from 3.75 to 67 for bicycling on streets. The relative risk of injury on the cycle track was 0.72 (95%CI=0,60-0.85) compared with bicycling in the reference streets.
  • Cycle tracks lessen, or at least do not increase, crash and injury rates compared to bicycling in the street.

Dr Lusk also said that intersections had to be well designed and the ideal was to have red and green bicycle traffic lights.

The researchers were not suggesting that cycle tracks had no risk for riders but the rigorous research showed that the difference in the accident rate was real.

Read the full study at http://injuryprevention.bmj.com/content/early/2011/02/02/ip.2010.028696.full

See an interview with Dr Lusk at: http://www.bicyclecity.com/anne-lusk-interview.

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