Northbound San Jose Avenue & I-280 Off-Ramp Road Diet Pilot Project
The “Bernal Cut” section of San Jose Avenue between the I-280 off-ramp and Randall Street hosts freeway-like conditions on a city street. This problem is partially fed by a two-lane off-ramp from northbound I-280, which was widened from a single lane to accommodate detoured traffic after the 1989 Loma Prieta earthquake, which necessitated the closure of the Central Freeway.
The goal of the pilot project is to increase safety and comfort for all road users, including those who walk, drive, and bike along northbound San Jose Avenue, by reducing vehicle speeds along a city street that has long been configured like an urban freeway.
Prior to 1992, the northbound I-280 off-ramp at San Jose Avenue consisted of a single lane. After the 1989 Loma Prieta earthquake, large sections of I-280 and the Central Freeway closer to Downtown were closed for repairs, and the off-ramp to San Jose Avenue was widened to assist traffic arriving in San Francisco. When the retrofit work was completed, the ramp was not reduced back to its original single lane width.
Neighborhood residents have expressed concerns about high vehicular speeds on northbound San Jose Avenue and the negative effects this speeding has on the safety for those who walk, drive and bike along the corridor. Adjusting San Jose Avenue into a city street from its current freeway-like configuration was a vision of the Glen Park Community Plan. In addition, the SFMTA has identified a portion of this section of San Jose Avenue as part of the Vision Zero High-Injury Network for vehicle collisions. After an initial community engagement period initiated by District 8 Supervisor Scott Wiener, the SFMTA designed a Road Diet Pilot Project intended to:
- Increase safety for those who walk, drive and bike along the corridor
- Reduce traffic speeds on northbound San Jose Avenue by reducing the number of traffic lanes on the I-280 off-ramp and on San Jose Avenue
- Upgrade the existing northbound bicycle lane with a wider, more separated bikeway (where space allows)
- Facilitate safer turning movements to and from northbound San Jose Avenue and adjacent residential streets
- Reduce cut-through traffic from northbound I-280
PILOT PROJECT IMPLEMENTATION
In June 2014, the SFMTA implemented Phase I of the San Jose Avenue Road Diet Pilot Project. Several low-cost measures were installed in order to reduce vehicle speeds on the street and increase safety of road users, with the goal of a 15 mph reduction in the 85th percentile speed by the end of the project. These included:
- Merging the left lane of the San Jose Avenue off-ramp with the northbound lane from San Jose Avenue that passes underneath I-280;
- Reducing San Jose Avenue from three to two lanes north of St. Mary’s Avenue, then opening the roadway back up to three lanes just south of Randall Street to maintain the traffic calming effect of the road diet; and
- Upgrading the San Jose Avenue bicycle lane to a more comfortable and separated bikeway (where space allows)
After the completion of Phase I, the SFMTA conducted a comprehensive evaluation of the effects of the road diet on vehicle and bicycle traffic. The evaluation found that, while vehicle speeds did decrease, the change was relatively minor, with the 85th percentile speed dropping only 6%, from 49 to 46 mph. Bicycle traffic on the street increased significantly, and minor increases in vehicle delay were detected at peak hours. Some side streets experienced increases in traffic volumes, possibly as a result of delays on San Jose Avenue.
As the City’s goal to reduce vehicle speeds on San Jose Avenue by 15 mph was not achieved in Phase I of the pilot project, in June 2015 the SFMTA implemented Phase II in partnership with Caltrans, which is responsible for the I-280 off-ramp itself. This phase:
- Maintained Phase I changes on the surface street portion of San Jose Avenue; and
- Merged the two lanes of the I-280 off-ramp into a single lane south of the existing I-280 tunnel, which then merges with the Monterey Boulevard lane
Following Phase II, SFMTA, in partnership with Caltrans, will be collecting and analyzing data to help determine a final configuration to recommend in coordination with repaving in 2016. This recommendation will take into account:
- Travel time surveys
- Vehicle speed and volume surveys
- Collision history
- Community feedback
TIMELINE AND NEXT STEPS
- June 2014 – Phase I of the Pilot Project was implemented by SFMTA.
- June 2015 – Phase II of the Pilot Project was implemented by SFMTA and Caltrans.
- Fall 2015 – SFMTA and Caltrans will continue to collect data to monitor traffic, speeds, and congestion once school is in session). Data collected will include traffic counts, speeds, travel time surveys, and community feedback.
- Winter 2015 – If the pilot project successfully slows speeds, SFMTA staff will recommend it as a permanent roadway configuration to the City Traffic Engineer.
- Early 2016 – SF Public Works will repave northbound San Jose Avenue with the configuration ordered by the City Traffic Engineer.