The new 2009 Manual of Uniform Traffic Control Devices is out and there is a subtle but important conflict between the MUTCD description of sharrows and how SDOT is describing and deploying sharrows.

The bicycle section of the new 2009 MUTCD can be found here:
http://mutcd.fhwa.dot.gov/pdfs/2009/part9.pdf

MUTCD:

A. Assist bicyclists with lateral positioning in a shared lane with on-street parallel parking in order to reduce the chance of a bicyclist’s impacting the open door of a parked vehicle,

B. Assist bicyclists with lateral positioning in lanes that are too narrow for a motor vehicle and a bicycle to travel side by side within the same traffic lane,

C. Alert road users of the lateral location bicyclists are likely to occupy within the traveled way,

D. Encourage safe passing of bicyclists by motorists, and

E. Reduce the incidence of wrong-way bicycling.

Seattle Guidelines for Sharrows:

Shared lane pavement markings (or “sharrows”) are bicycle symbols carefully placed to guide bicyclists to the best place to ride on the road, avoid car doors and remind drivers to share the road with cyclists. Unlike bicycle lanes, sharrows do not designate a particular part of the street for the exclusive use of bicyclists. They are simply a marking to guide bicyclists to the best place to ride and help motorists expect to see and share the lane with bicyclists.

What do sharrows mean for motorists and bicyclists?

Motorists:
• Expect to see bicyclists on the street
• Remember to give bicyclists three feet of space when passing
• Follow the rules of the road as if there were no sharrows

Bicyclists
• Use the sharrow to guide where you ride within the lane
• Remember not to ride too close to parked cars
• Follow the rules of the road as if there were no sharrows
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There’s really a subtle difference which confuses many people, drivers and cyclists both. The MUTCD essentially states that Sharrows are to assist with lateral positioning, i.e. taking the lane since the lane in which sharrows are to be used is too narrow for a vehicle and a bicycle to use the lane at the same time. All the points describe this situation.

The Seattle guidelines are somewhat different. They state that sharrows are to let cyclists know where the best place in the roadway is to ride, i.e. subtly giving the impression that where the sharrow is placed is where to ride. The bullet point drives this home: “Use the sharrow to guide where you ride w/in the lane” which is incorrect.

The sharrow according to MUTCD gives cyclists the lane, the Seattle description gives cyclists the sharrow area. And Seattle by not using standard sized, centrally placed sharrows only adds to the confusion. For example, using minimum standards doesn’t cut it on routes like Fauntleroy southbound. There the vehicles and cyclists are encouraged to share the lane at the same time because it wasn’t wide enough to add a bike lane southbound – which has not made cycling any easier on that newly sharrowed route.

We suggest that Seattle:

1. Remove the ”use the sharrow as a guide where you ride within the lane” language until Sharrows are placed to take the lane.
2. Move Sharrows further to the center of the lane.
3. Add the new R4-11 sign on routes with Sharrows to help clarify that Sharrows are not a bike lane, but an indication that the lane is too narrow to split.
   
4. Remove old “Bike in a House” style sharrows and sharrows that are less than 2 feet from the curb like this one that we previously mentioned on the Missing Link.
   

Thanks to Aili for her initial analysis and descriptions used in this story.