The SFMTA recently made a number of bicycle improvements along Portola Drive, from Sloat Boulevard to Market Street. These changes include protected bikeways, bicycle lanes, and shared roadway markings ("sharrows"). Over the past few months since the installation, citizens and SFMTA staff have noted various elements of the design that would benefit from additional modifications.
Modifications to Portola Drive Bicycle Lanes
The SFMTA plans to make a variety of modifications to Portola Drive by the end of the winter season. These improvements include:
- Clearer traffic lane markings for the left turn from Portola Drive to Fowler Avenue
- An improved pedestrian crosswalk crossing Fowler Avenue at Portola Drive
- A redesign of the bicycle lane and right turn lane on eastbound Portola Drive between Glenview Drive and Diamond Heights Boulevard
- Clearer traffic lane markings guiding vehicles through the intersection of Portola Drive and Diamond Heights Boulevard/Burnett Avenue
Clarifications on New Portola Drive Design
The SFMTA has also received comments and questions from the public regarding elements of the project that should be clarified, pertaining to the left turn from Portola to Fowler, and the use of downhill sharrows rather than a bike lane.
Left turn from Portola Drive to Fowler Avenue:
Prior to the project, two left turn lanes on Portola Drive led to Fowler Avenue and the parking lot. One of the two turn lanes was removed to make room for the curbside bike lane (not the bike lane now alongside the turn lane). It is acknowledged that there are currently few cyclists making a left turn there, but the left turn bike lane was added as there was space available for it. The second turn lane for motorists would have been removed regardless. Upcoming changes to the area include restoration of lane markings near Fowler Avenue to clarify movements for both motorists turning left into the parking and for continuing onto Fowler Avenue, and higher visibility crosswalk markings and signs.
Some would rather see a downhill bike lane along Portola Drive leading to Sloat Boulevard, but SFMTA staff determined that sharrows would be more appropriate due to the higher speeds of cyclists in the downhill direction, the increased ability to keep up with traffic and take the lane, and the desire to keep cyclists out of the parking door zone (where suddenly opened doors could strike a cyclist).
To add a bike lane and remove this parking door zone concern, all the parking along the north-west side of Portola Drive would have had to be removed. In the uphill direction where bicycle speeds are slower, "doorings" are more avoidable.