Potrero Avenue Corridor Project

Project Summary

Project Background

Project Location Map

Project Background

Meeting Schedule and Locations

Frequently Asked Questions

Data, Figures and Photographs

Public Feedback

The re-striping of Potrero Avenue between 25th Avenue and 17th Street was completed in August of 2005. The associated signal improvements on Potrero Avenue between 16th and 25th Avenue were completed in the Summer of 2006. These improvements include new dedicated turn phases, new pedestrian count-down signals and devices to detect the approach of buses and make minor adjustments to the phasing to reduce signal delays to the bus.

The initial median improvements included in this project have also been completed.  These improvements include new raised median pedestrian refuges and a new mid-block crossing in front of San Francisco General Hospital.

Since the project’s completion, there have been several minor adjustments to the signal timing progression to facilitate smoother traffic flows.

MTA staff will also be continuing to investigate how these lane changes may have impacted traffic patterns and volumes on nearby residential streets, and whether additional traffic calming measures should be considered.

The Department of Parking and Traffic completed the initial public outreach component of the Potrero Avenue Corridor Livable Streets Program in September of 2004. Two community meetings were held at the San Francisco General Hospital and DPT staff conducted a walk-through to address specific design issues. These meetings served to present DPT’s analysis and initial arterial traffic calming plan for Potrero Avenue.

DPT’s preliminary efforts explored the traffic implications of removing two of Potrero Avenue’s six through-traffic lanes, one in each direction. The traffic analysis indicates that for most parts of the day, Potrero Avenue handles traffic volumes well below its capacity. However, as congestion levels on the parallel Bayshore Freeway increase, traffic volumes on Potrero Avenue can also increase significantly as motorists seek alternative ways into and out of downtown San Francisco. A review of existing City and Caltrans count data and casual observation indicates that such conditions are not a daily occurrence, but like the Bay Bridge Approach occur two or three days out of a week.

DPT’s initial plan identified a relatively low cost, pavement marking based solution that staff felt could be implemented in a short frame, and one that would not preclude the Potrero Avenue “Bus Rapid Transit” (BRT) improvements specifically identified in Proposition K (approved by San Francisco voters in November of 2003).

Because Potrero Avenue is already a dedicated City bicycle route, the installation of bicycle lanes was eligible to receive, and was awarded grants from the Bay Area Air Quality Management District. DPT’s initial plan proposed to eliminate two traffic lanes allowed a new set of 5’ bicycle lanes in each direction and a 14’ space in the center that could (for most of the length of the study area) accommodate a shared left-turn lane at mid-block locations and several dedicated left turn pockets.

At the public meetings there was some initial concern about the 20 parking spaces in the study area that would be necessary to relocate in order to lengthen the typical 70’ existing bus stops to meet Muni’s 100’ minimum length standard.

Since the initial public meetings in late August of 2004, DPT has received overwhelming support for its traffic calming efforts from the Community. Understandably there has been some concern about the potential loss of parking due to bus stop improvements.

While not disputing the need for safety improvements on Potrero Avenue or the need for a reduction in traffic capacity, Muni’s operators have expressed their concern that the installation of dedicated bicycle lanes on Potrero Avenue as originally designed by DPT may make it increasingly more difficult for their operators to safely reach their curbside stops, and the additional congestion caused by the lane reduction will adversely impact scheduled transit service on Potrero Avenue. In addition, Muni felt that dedicated bicycle lanes installed on an interim, temporary basis would be difficult to reclaim later for bus lane purposes.

On Thursday, October 28, 2004, DPT conducted a limited, temporary lane closure test at 25th and (NB) Potrero on October 28 to better understand how the northbound morning peak-hour traffic on Potrero Avenue will operate with one less traffic lane. Just south of the eastern leg of 25th Street, the southbound US 101 off-ramp to Potrero Avenue hooks around the Potrero del Sol Park and joins up with Bayshore Boulevard to create Potrero Avenue’s third lane. The volumes on this ramp structure are fairly light…less than 200 vehicles per hour. When the lane closure test was conducted, Potrero Avenue ran fairly smoothly. US 101 appeared to be operating without incident. From our vantage point at 25th Street during the test, the permissive unsignalized northbound left turn at 25th Street appeared to create the most congestion while waiting for gaps in the southbound traffic.

Other staff reported seeing instances at 25th and Potrero whereby the crossing guard was having difficulty protecting the crosswalks from westbound vehicles on 25th Street making left turns to head south on Potrero.

The Potrero Avenue Livable Streets Corridor focuses on that portion of Potrero Avenue between 25^th Street on the south and 17^th Street on the north. Once a primary entrance into and out of the City, Potrero Avenue runs parallel to US 101 the Bayshore Freeway. Located less than two miles south of San Francisco’s Financial District the Avenue is characterized by a mixture of residential homes and apartments and smaller commercial establishments and health related facilities. San Francisco General Hospital dominates the eastern side of Potrero Avenue between 21^st Street and 23^rd Street. Potrero Avenue is flanked by the Mission District to the west and the Potrero Hill neighborhood to the east.

Figure 1: Project Location Map

DPT began this effort earlier this year by analyzing traffic on Potrero Avenue and intersecting streets to ensure that the traffic lanes can be removed without impacting Muni and SamTrans bus service or significantly reducing the capacity for through traffic on Potrero Avenue. This proposal has recently been reviewed and approved by the Interdepartmental Staff Committee on Traffic and Transportation, which includes representatives from the Fire and Police Departments as well as other city agencies responsible for reviewing such roadway changes.

The proposal is to install bike lanes and new pedestrian refuge islands on Potrero Avenue, from 17th to 25th Streets, by reducing the existing traffic lanes from three lanes to two in each direction and by adding new left turn lanes in the center. This portion of Potrero is a designated bicycle route. To improve Muni’s bus operation on Potrero Avenue, the project also proposes to lengthen those bus stops which currently do not meet Muni’s current minimum standards and add transit-friendly signals on Potrero Avenue. The overall project will also add pedestrian countdown signals to assist pedestrians crossing Potrero and cross streets.

Figure 2: Bicyclist riding northbound on Potrero	Figure 3: Muni's #9 San Bruno line provides frequent service along Potrero Avenue

Why doesn’t the project extend north to connect with Division?

One of the conditions of the grant used to partially fund these bike lane improvements requires that any new bike lanes created be on an established bicycle route on a pre-existing bicycle network plan.

Go to San Francisco DPT’s Bicycle Program Planning Website
View/Download a PDF version of San Francisco's Bicycle Map

Potrero Avenue between 25^th and 17^th is officially designated as a bicycle route 25. At 17^th Street, bicyclist wishing to continue traveling north can do so via the bike lanes on Harrison Street to the west, or travel east on 17^th to Kansas Street to continue into the City on 7^th Street or Townsend Street.

DPT staff supports efforts to extend the bike lanes northward, but such efforts will likely need to be part of another project.

Can there be significant pedestrian improvements without the loss of a lane?

Based on an analysis of existing traffic conditions and historic collision records and responding to the community’s desire to improve the livability of Potrero Avenue and other arterials in the area, DPT has developed a project that is expected to have relatively minor traffic impacts and significant safety benefits for the pedestrians and bicyclists that all use Potrero Avenue.

It is difficult to safely accommodate pedestrians on a six-lane undivided arterial with high speeds. By eliminating two of the existing six lanes, additional space can be reallocated to bicyclists and pedestrians at key conflict locations. This reconfiguration balances the needs of the Potrero Avenue community without unduly interfering with the needs of the many motorists who rely on Potrero Avenue to reach their final destinations in and out of the City. The proposed configuration proposes to eliminate travel lanes where they are under-utilized and replaces them with more efficient lanes designed to minimize the delays attributable to vehicles making left-turns. The lane reduction plan also serves to minimize the number of lost parking spaces.

Why must the bus stops be lengthened?
Why must the Community lose even more parking spaces?
Buses never use the stops they have!

In the course of the project design, it was determined that many of the existing bus stops on Potrero Avenue do not meet Muni’s minimum length standards. As part of the re-stripping project it was determined that the re-stripping project would be a good time to lengthen these stops and make them compliant and readily accessible to buses

Figure 4: Historical 12 Hour Volume Trends on Potrero Avenue

Figure 5: Northbound Traffic Volumes on Potrero North of Mariposa

Figure 6: Southbound Traffic Volumes on Potrero North of Mariposa

Figure 7: Muni Bus Stop at 24th and Potrero

Figure 8: Pedestrians Cross Potrero near Mariposa

Overall, MTA staff felt that the public response to the Potrero Avenue changes was more supportive than other similar lane reduction projects.

"…Potrero looks incredible! We are SO SO thrilled, and it's 100 times better for cars too, I LOVE the turning lanes. Thanks a million…"

"…I've been happily commuting on the new bike lanes on Potrero every morning. It seems to be working well (though cars do intrude on the bus lane). I've even seen a decrease in the left turns onto 25th!..."

"…Thank you again for the fabulous new boulevard!"

"…Let me know if I can be of help in the planning for the north stretch of Potrero."

"…16th St corner of Potrero is still such a hazard.  Can we get Muni bulb-outs, in the short term (NE & SW corner on Potrero), before having an extended bike lane discussion?  It is nearly impossible to cross that corner safely, and a median would get in the way of left turns (which we need) into 16th St…"

Contact Info
Livable Street Hotline: 415-554-2398
Livable Streets E-Mail: livable.streets@sfgov.org
San Francisco Municipal Transportation Agency, Livable Streets Subdivision
1 South Van Ness Avenue - 7th Floor
San Francisco, CA 94103