New study shows Highway 101 express lanes have improved but some transit experts wary

The current express lanes, which opened several years ago, stretches 22 miles on Highway 101 from the Santa Clara County line to Interstate 380. Starting around 2020, the TA began conducting research on expanding the project, either by converting an existing lane into an express lane or constructing a brand-new one.

Many transit advocates have opposed the plan, especially the latter option.

The recent study presented at the TA board meeting April 2 showed that the average speed in the express lanes increased between 7-13 mph between 2018 to 2024, and the general purpose lane speeds increased by 1-7 mph.

Other key findings showed a 16% reduction in vehicle hours traveled — suggesting drivers are arriving to their destinations quicker — and a 22% reduction in peak period carbon dioxide emissions. Southbound express lane users saw a 22% reduction in travel time, while northbound users saw 13% reduction.

But some leaders and transit advocates have questioned the data and methodology surrounding the congestion improvements.

Board Member Carlos Romero, also a member of the East Palo Alto City Council, said that widening the highway by adding another lane tends to induce demand, which over time, will start to eat up the earlier gains, also adding he had concerns over the study’s methodology.

“I think it’s problematic to have this data that is a little scrambled. We have data that is pre-COVID … but I’m not sure that we have reached [a steady state] post-pandemic,” Romero said. “I’m very much hoping that perhaps in a year from when this study was done, we do a follow up with cleaner data.”

About a month ago, transit leaders also discussed express lane ridership performance, which raised another concern about inaccurate data, specifically related to carpooling. Drivers with three or more passengers can travel the express lanes toll-free by toggling a declaration on their FasTrak. Two-person carpools receive a 50% discount, while single-occupancy vehicles pay full price, which averaged $4.05 northbound and $5.29 southbound last quarter.

The approach is mostly based on an honor system, which has cast doubt on the accuracy of the carpooling data among some, given that nearly half of express lane trips are toll free. The TA has been concerned about the accuracy for some time, but recent data from the California Highway Patrol confirms the issue isn’t resolving on its own and may necessitate more investment in better monitoring and tracking capabilities.

The initiative to potentially expand the express lanes north of Interstate 380 is in the environmental and preliminary design phase, which is now expected to be completed in summer 2027.

Correction: The story has been updated to show that the average speeds increased, not decreased, in the express lanes and general purpose lanes between 2018 and 20224.