Congestion Pricing Study of San Francisco–Oakland Bay Bridge in California

The San Francisco–Oakland Bay Bridge in California is one of the most heavily traveled corridors in the United States. A study on congestion pricing was performed to address traffic congestion in this corridor. Existing toll plaza counts and travel time data were used in the estimation of traffic demand by applying queuing analysis. Regression analysis was conducted to estimate the number of drivers who would shift to other modes in response to the congestion pricing. Five congestion pricing alternatives were examined. The bigger the price differential between peak and nonpeak toll, the more delays, queue length, and duration of congestion were reduced. Of the five alternatives, the one with a $2.00 price differential between peak and nonpeak toll was selected and implemented on July 1, 2010. This adopted congestion pricing strategy was to reduce the traffic demand by 4.2% and 5.0% in the a.m. and p.m. peak periods, respectively. The congestion pricing was to reduce significant delays (24% to 30%) by removing only a fraction of the vehicles (4.2% to 5.0%) from the congested Bay Bridge. A preliminary analysis comparing traffic counts between July and September 2009 and July and September 2010 found that, in July, traffic volume decreased by 8.4% and 7.3% during the a.m. and p.m. peak periods, respectively. In September, traffic volume decreased by 6.0% and 3.9% during the a.m. and p.m. peak periods, respectively. A comprehensive evaluation study is under way to identify changes due to congestion pricing and changes due to a multitude of exogenous factors.