Study: Two-Way Bike Lanes Produce More Injuries

Photo: GHSA
Photo: GHSA

A new study is finding that the safest bike facilities on busy streets are Dutch-style, sidewalk-level bike lanes or protected bike lanes with no driveways or intersections, such as those on bridges.

And a surprising number of injuries are happening in two-way, street-level, protected bike lanes.

The Insurance Institute for Highway Safety study recently analyzed 350 bike-injury cases in New York, Washington and Portland in order to determine which street designs were safest for those on two wheels. The study surveyed injured riders who were treated in hospitals.

“Two-way protected bike lanes alongside two-way vehicle traffic add … complexity as turning drivers need to monitor both oncoming vehicle traffic and two-way bicycle traffic in the bike lane,” author Jessica Cicchino and her research team wrote.

Researchers found that calm, residential streets were the safest places for riding. But even unprotected bike lanes had lower injury rates than two-way, protected street-level bike lanes, the study showed.

Most injuries the study examined were minor, and only about half involved cars — including injuries from falling off a bike to avoid a car or crashing into a parked car.

Cicchino and her team noted that protected bike lanes work well at reducing the most dangerous crashes for cyclist — mid-block, high-speed, from-behind collisions with cars. But protected bike lanes with many intersections — especially two-way lanes — produced many conflicts, including conflicts with pedestrians, the study found.

The authors stressed that the potential for conflicts doesn’t mean that protected bike lanes are worse for safety than nothing. Rather, the findings indicate the need for careful engineering and more safety research.

The authors recommended countermeasures to reduce pedestrian use of two-way, protected bike lanes, including placing bike lanes at sidewalk level. Two-stage turn boxes, protected intersections, and special traffic signal with phases for cyclists also could help reduce more minor injuries, they wrote. Planners should try to avoid places with many driveways when considering where to install protected bike lanes, the study said.

One limitation of the study was that the authors did not compare the safety of the different bike lanes based on the severity of injuries that occurred in them. The study also did not control for the busyness of streets; those with two-way, protected bike lanes may have been the most crowded with drivers and pedestrians, producing more conflicts.

9 thoughts on Study: Two-Way Bike Lanes Produce More Injuries

  1. “Another excuse oft heard is, “Well… it’s better than nothing” – often spoken in a defensive tone. It is a flawed argument, lacking vision, commitment and experience.” – Copenhagenize.com in its article http://www.copenhagenize.com/2014/06/explaining-bi-directional-cycle-track.html

    US municipalities build two-way bike lanes because they take less road space from car driving and parking lanes. Making two one-way lanes on a street would, if built to NACTO standards, take more space.

    Two-way bike lanes are political compromises that reflect our lack of “commitment” to building safe facilities. What’s annoying is that IIHS’s Cicchino didn’t explain this, as if the political context doesn’t matter. It does, since every inch of road space is contested terrain.

    Equally frustrating was the assertion that door zone lanes are safer than two-way PBLs. I know of many people who choose not to cycle anywhere except on PBLs. And if they claim the door zone lanes are safer because they’re on calmer streets, then what about PBLs on calmer streets? Seems like an apples to oranges comparison.

  2. “The study also did not control for the busyness of streets; those with two-way, protected bike lanes may have been the most crowded with drivers and pedestrians, producing more conflicts.”

    This is a HUGE limitation to the study, and there really is no excuse for it. Vehicle volumes are readily available or obtainable, even if accurate walker counts are hard to come by.

  3. Wait, what?
    “The authors recommended countermeasures to reduce pedestrian use of two-way, protected bike lanes, including placing bike lanes at sidewalk level.”
    How does effectively putting bikes on the sidewalk keep pedestrians out of them?

  4. Did they look at two-lane PBLs on one-way streets? The intuitive expectation would be that it’s easier for motorists to deal with a two-lane PBL when you reduce the number of directions other motorists can be coming from, so it’d be useful to have actual data showing whether that bears out.

  5. “I told you so” is not nearly as satisfying as actually having planners listen to cyclists with long experience of the dangers of various “solutions” to bike safety. We already knew that wrong way salmon cyclists (and pedestrians) were most at risk of being hit by drivers looking for oncoming traffic at intersections. It was obvious that putting a bi-directional cycletrack along a busy road would create the same situations for opposite flow riders. I wrote to local bicycle advocates in SF and Marin county explaining the real problems with forcing cyclists outside of drivers’ visual focus zones, my history of successful bicycle policy actions, and offering my evidence based signs for free educational materials, but they ignored me.

  6. We have a two-way PBL on a one-way street in downtown car-loving Houston. At the intersections, the PBL has its own signal light that triggers a few seconds before the pedestrian and car signals do. That gives the bikes a fighting chance to get across the street or at least be very visible in the middle of the intersection before the turning cars can get there. Why the ped light doesn’t go at the same time, I don’t know.

  7. The two-way streetside cycletrack that runs east–west thru downtown Houston is a monument to incompetent bikeway design. It’s narrow (eight feet, measured from the curb face, containing both directions of bike movement); it’s constantly perforated by midblock driveways that carry MVs into and out of multi-story parking garages, it’s aligned when in several places it occupies the same space where heavy commercial vehicles must do their loading and unloading; and at all signalized intersections (which happen every 300 feet), there is NO signal-phase separation of thru bike traffic from turning motor traffic. It’s an absolute disgrace. And yet, local “advocates” and city planners want more, more, more of the same! Idiots.

  8. The two-way streetside cycletrack that runs east–west thru downtown Houston is a monument to incompetent bikeway design. It’s narrow (eight feet, measured from the curb face, containing both directions of bike movement); it’s constantly perforated by midblock driveways that carry MVs into and out of multi-story parking garages; it’s built where in several places it occupies the same space that heavy commercial vehicles must use to do their loading and unloading; and at all signalized intersections (which happen every 300 feet), there is NO signal-phase separation of thru bike traffic from turning motor traffic — even the streets that cross it have no prohibition against turning across the bikeway against a red signal (when the bike signals are green in both directions). It’s an absolute disgrace. And yet, local “advocates” and city planners want more, more, more of the same! Idiots.

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