Bay Bridge Toll Evaluation Reveals Surprises

January 19, 2012
A year-long study into the effects of increased tolls and congestion pricing on Bay Bridge traffic conditions has revealed a number of surprising changes in travel behavior, according to Karen Frick, Assistant Director of the UC Transportation Research Center.
A team of ITS-affiliated researchers, led by City and Regional Planning Professor Elizabeth Deakin of the Global Metropolitan Studies Center, evaluated changes brought about beginning in July 2010 when congestion pricing and tolls for previously free carpool lanes went into effect.
Frick presented the team’s final report to the Bay Area Toll Authority oversight committee on November 9 at MTC headquarters in Oakland.
Among the results, the researchers noted:
  • Carpool lane usage declined by 26 percent, while vehicles using the cash/FasTrak lanes increased by three percent.
  • Some drivers and carpoolers moved to off-peak periods to avoid the higher toll.
  • Travel times improved substantially during certain hours and from some approaches to the bridge, but not all. 
  • BART is carrying 10-15 percent more riders across the Bay, some of whom are former Bay Bridge drivers and carpoolers. 
  • Business owners made few changes in practices due to the toll increases, and those who depend on high-cost labor or timely deliveries support congestion pricing as a benefit to them and their employees.
“A big question, of course, is where have all the carpoolers gone,” said Frick, noting that carpool counts declined by 4,365 vehicles. With three people per vehicle, that amounted to 13,000 people who might have become solo drivers. But with only 3,300 more vehicles in the cash/FasTrak lanes the researchers suggested that former carpoolers found alternatives.
Some moved to BART, some chose to travel off-peak when tolls were lower, and some were not carpools to begin with, but were using the carpool lane illegally.
Others, said Frick, decided to continue to carpool but only with one other person, such as a family member. “With the added charge to the carpool lane, some felt it just wasn’t worth it to stop and pick up a third person.”
She also stressed that during the year-long study period, changes in economic conditions also played a role in decreasing carpool numbers. Jobs vanished or changed locations; families moved.

Related discoveries

The imposition of a $2.50 carpool charge also created a “major change in carpool dynamics—in how to pay the toll.” Frick said. Casual carpool passengers in Vallejo typically pay drivers $1.25, while those at some East Bay sites offer drivers $1. Some drivers do not ask riders to share the toll.
“There is still some tension around this. Commuters are still trying to work it out,” Frick added.
One of the biggest surprises, however, was the discovery that about 60 percent of those who drive over the bridge find free or employer-subsidized parking in San Francisco, a powerful incentive to drive rather than take transit. Even with the increased toll, these commuters still save money by not having to pay for parking.
“Some of these drivers park in on-street spaces they have found,” she said, adding, “Of course, they won’t tell us where they are.” She said this may change as SF Park, the advanced parking management system which uses sensors, new meters and real-time parking data, continues to identify and incorporate city parking spaces into its program.
At the conclusion of her presentation, MTC Commissioner Amy Worth, thanked Frick for her presentation, adding that she loved the idea that “an army of UC Berkeley students” was able to apply their talents and energy to this project.
Besides Deakin and Frick, the research team included Robert Cervero, Director of UCTC, Alex Skabardonis, Professor-in-Residence, as well as a large group of graduate students.  
--Christine Cosgrove