San Mateo County Highway 101 Expansion Moves Ahead With Express Lanes

San Mateo County’s effort to expand Highway 101 from eight to ten traffic lanes moves ahead next month when an $11.5 million update of the project’s environmental review begins. County transportation officials had planned since 2009 to expand the highway with standard carpool lanes, but agreed last year to consider installing Express Lanes as well, an option favored by the Metropolitan Transportation Commission (MTC).

Express lanes are free for buses and carpools, but charge a toll to solo drivers during congested hours to ensure the lane remains free-flowing, and have been installed on Highways 680, 880, 580, and 237. If built on Highway 101 in San Mateo County, express lanes would someday extend for 58 miles from San Bruno through San Mateo and Santa Clara counties to Morgan Hill.

“The idea here is that we would create a more reliable travel time within that lane and that overall we increase the person throughput,” explained San Mateo County Transportation Authority (SMCTA) Deputy Project Manager Leo Scott to the agency’s Board of Directors in May when the express lane options were announced. “We only expect more trips later, and with limited right-of-way, the best use of [Highway 101] is to get more people in fewer vehicles.”

The City/County Association of Governments (C/CAG) of San Mateo County, responsible for the highway project’s environmental review, originally favored widening a 14-mile segment of Highway 101 between San Bruno and Redwood City from eight to ten lanes with standard carpool lanes. But MTC predicts those new lanes would be jammed with traffic the day they opened – in 2024 at the earliest. The new carpool lanes will have cost up to $215 million, according to an April 2016 project update by Caltrans [PDF].

But converting an existing lane on the highway to an express lane would move traffic faster in all lanes and carry more people in fewer vehicles, according to analyses conducted by MTC in 2015 [PDF] and TransForm in 2013 [PDF]. Such a lane could also be installed for $109 million in as little as three years. Corporate bus fleets, now stuck in the same slow-moving traffic as solo drivers, are expected to expand with faster-moving and reliable express lanes. Revenues from the tolls charged to solo drivers could be invested in better transit service, possibly including public buses on the highway, rather than paying off the extra $100 million in construction costs needed to widen the highway to ten lanes.

“If [conversion of an existing lane to an express lane] is selected as the preferred alternative, it is anticipated that it would require an increased use of buses, vans and carpools (mode shift from single occupant vehicles),” states the April 2016 project update.

This scenario depends on successfully shifting about 10 to 15 percent of solo drivers on the highway to transit and carpools, cutting traffic by 1,000 vehicles an hour. MTC proposes reinstating express SamTrans bus service cut in 2010 and providing new highway bus service, expanding private employer shuttles, and increasing carpooling. Private employers would need to beef up their own Transportation Demand Management (TDM) programs to further cut solo driver trips.

County transportation officials estimate that the Highway 101 project’s environmental review will take 28 months, after which carpool lanes or express lanes could be installed if funding is available.