Potrero Avenue between 55th and 56th Street

Safety Improvements Project

Potrero Avenue has four closely spaced intersections within approximately 500 feet from east to west as follows: stop-controlled at S. 55th Street, uncontrolled at the WB I-80 On-Ramp, signalized at Eastshore Boulevard/I-80 Eastbound Off-Ramp and stop-controlled at S. 56th Street. This area has a disproportionately high collision rate, which was confirmed by a Traffic Safety Audit conducted by the City in 2006. The project specific improvements include:

  • Extend the left-turn lane at the I-80 Westbound On-Ramp westward to S. 55th Street, and modify the centerline west of S. 55th Street. Presently drivers on eastbound Potrero Avenue are confused seeing cars moving in opposite directions and signaling a left turn. They have trouble assessing if the cars are turning onto I-80 Westbound on-ramp or onto 55th Street.
  • Remove the right-turn island at the I-80 Eastbound Off-Ramp. Eliminating the free (“uncontrolled”) right-turn movement is expected to address safety concerns created by the limited sight distance and short merging distance between the I-80 Off-Ramp and S. 56th Street, as well as, improve pedestrian safety.
  • Modify and upgrade the traffic signals at this intersection to provide protected left-turn phasing for the I-80 Eastbound Off-Ramp, Eastshore Boulevard and Potrero Avenue approaches. The new left-turn phasing will assign right of way as well as address sight distance problems created by the existing roadway alignment
  • Modify the median at S. 56th Street and prohibit parking at the very end of northbound 56th Street. The current shape of the median obstructs northbound left turns from S. 56th Street to westbound Potrero Avenue. The three existing parking spaces along the east curb of E. 56th Street obstruct and delay northbound drivers turning right to eastbound Potrero Avenue. This delay causes drivers to become frustrated and accept less than optimum gaps in traffic. Prohibiting on-street parking from 3 to 6 p.m. on weekdays and striping a right-turn lane is expected to facilitate the left turns as well.
  • Add a crosswalk on the west leg of Potrero Avenue, where none exists now.
  • Modify the median on Eastshore Avenue.
  • Add bicycle detection and pavement markings.
The project is expected to result in the reduction of the predominant collision patterns along this roadway segment, for motorists and bicyclists. The project will bring all elements of the intersection to the latest requirements of ADA (Americans with Disabilities Act) and make accommodations for pedestrians, bicyclists, and transit vehicles. The project involves State right of way under the I-80 freeway, and will require a Caltrans Encroachment Permit.

A federal grant of $584,910 from the Highway Safety Improvement Program (HSIP) is funding 90 percent of the project. The local match of $64,990 is funded by Measure J and Proposition 1B as shown in the current Capital Improvement Program under Project C-3045.