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Plans for Polk Street Bike Lane Changed From Raised to Road Level

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Friday, February 3, 2017

Bike lane at road-level, with green-painted pavement and plastic posts separating it from vehicle traffic.
In light of findings on raised bike lanes on Market Street (shown here before it was raised), Polk Street's northbound bike lane will now look similar to this.

With construction on Polk Street’s two-year transformation underway, we’ve made a change to the plan for a raised bike lane in light of our recent research on best design practices.

The previous plan for the Polk Streetscape Project included a raised bike lane, with a two-inch mountable curb, on the northbound side of Polk from McAllister to Pine streets. But in our experiment with different curb designs last year on Market Street, we found that raised bike lanes on commercial streets like Polk should have a parking-protected configuration, with a lane of car parking and loading zones between the bike lane and the roadway, to prevent drivers from parking in the bikeway.

Making room for that parking lane on Polk would require major changes to the plan already under construction. To make the bike lane safer without a major delay, the northbound bike lane will no longer be raised but will be built at road level with plastic safe-hit posts and a painted buffer zone to separate it from the traffic lanes.

A diagram of the plan for upper Polk Street, between Post and Pine streets. On the northbound side of the street is a bikeway at road level next to the sidewalk curb and plastic posts separating it from vehicle traffic. The plan also includes one traffic lane in each direction as well as a bike lane and car parking lane on the southbound side of the street.
Under the new plan, Polk Street’s northbound bikeway (right) will no longer be raised on a curb, and will be separated from traffic with a buffer zone and plastic “safe-hit” posts.

These measures will be more effective at deterring illegal parking and loading, and they could save on costs and time for construction. Since they won’t require changes to infrastructure like curbs, they won’t preclude further improvements.

As we refine designs for a new generation of protected bike lanes, we took this opportunity to make of one of the first bikeways safer and more inviting for people of all ages. Other raised bike lanes coming to Masonic Avenue and 2nd Street, where street transformations are also underway this year, won’t need these kinds of changes. Since Masonic is a residential street, and the bike lanes on 2nd will be parking-protected, they aren’t expected to face the same issues with parking and loading in the bikeway.

You can get the latest on the construction of the Polk Streetscape Project and sign up for weekly updates on the SF Public Works website.