Photo: Lea Suzuki / The Chronicle Photo: Lea Suzuki / The Chronicle Photo: Lea Suzuki / The Chronicle Photo: Lea Suzuki / The Chronicle Photo: Lea Suzuki / The Chronicle Photo: Lea Suzuki / The Chronicle

After years of frustration with the traffic on Highway 101 — the choked artery that links downtown San Francisco to suburbs and office parks on the Peninsula — San Mateo County officials are turning to buses as a solution.

SamTrans started a new line of roomy, Wi-Fi-equipped shuttles in August, serving a niche market of commuters who travel from Foster City to the Financial District and vice versa. Five buses depart from Hillsdale and Shell boulevards in Foster City between 6 and 8 a.m. weekdays, while an additional five head south from Drumm and Clay streets in San Francisco. The fleet includes regular 40-foot coaches with 38 seats, as well as 60-foot articulated buses.

The FCX commuter express is the first of six routes that will run from San Francisco to various neighborhoods of Silicon Valley, coinciding with efforts to build zippy express lanes on 101 and Interstate 280.

“There is no more important mission for public transportation right now than getting cars off the highways,” said Belmont City Councilman and SamTrans board Director Charles Stone. He rode the bus during its first several days of service and marveled at the number of passengers he met who characterized themselves as first-time transit riders.

The FCX already attracts standing-room-only crowds, mainly riders who said they previously drove or took a longer and more circuitous journey on mass transit. Several riders said they previously drove or took a longer and more circuitous journey on mass transit. Some parked at the Hillsdale Caltrain Station, rode the train to Fourth and King streets, then walked the last mile into downtown San Francisco. Others drove on 101 to the San Bruno BART Station.

Tech worker Jonathan Marsh said the difficult commute might have cost him a job. He started working in the Financial District in August, when the first FCX shuttles hit the freeway.

“Before that, I didn’t really have a way to get to the city,” Marsh said, hunched over a laptop as the bus eased down Drumm Street at 5:15 p.m last Tuesday when it was already a third full. By the time it reached Fifth and Mission streets, people were standing in the aisles.

The planned bus lines are byproducts of a study that SamTrans began in 2017 in an effort to tackle a problem on the 101 corridor: an explosion of job growth that’s far outstripped housing development. The surge of new jobs — San Francisco, San Mateo and Santa Clara counties added 254,000 from 2008 to 2015 — has made 101 one of the most economically productive corridors in the world. It’s also shown the deficiencies of a transportation system that operates county by county while trying to serve people, goods and services that move regionally.

Photo: Lea Suzuki / The Chronicle

As companies flourished in San Francisco and Silicon Valley, workers fled to suburbs and rural outposts in search of cheaper housing, a migratory pattern that put more cars on the roads. Highway 101 was already jammed with motorists traveling within San Mateo County, who account for 43% of rush hour trips on the freeway that cross Highway 92. Now, motorists heading north from the South Bay and southeast neighborhoods of San Francisco converge with supercommuters from the Central Valley and south of Gilroy, described by some as bedroom communities of the Bay Area.

The freeway also clogs up in the southbound direction, as San Francisco residents travel in greater numbers to work on the Peninsula. Models from the SamTrans express bus study predict that the majority of riders — 57% — will depart from downtown San Francisco or Potrero Hill to jobs in Foster City. Some may take a ferry in from Richmond or Larkspur and catch the bus across the street.

Buses provide an efficient way to carry people across county lines using existing transportation infrastructure and funds from a half-cent sales tax that San Mateo County voters approved last year. SamTrans crafted the six new routes for riders — and employers — who aren’t within walking distance of BART or Caltrain. Early next year, they’ll start a line from the west side of San Francisco to Palo Alto, followed by routes from East Palo Alto to San Bruno BART, from downtown San Mateo to downtown San Francisco, from San Mateo to San Francisco’s west side and from Burlingame to downtown San Francisco.

For people living in office-heavy but transit-hungry areas such as Foster City, the express bus adds ease and convenience. Brian Decal said it allowed him to commute from home to the Adobe office on Townsend Street “without hopping into a car.”

Still, it has one major shortcoming: It’s no faster than a car. It will take years for Caltrans to build the new freeway express lanes that would accommodate buses and carpools, as well as motorists who pay an extra fee. San Mateo County will probably widen the road, which requires more extensive design and construction than converting existing freeway lanes.

Until these express lanes open, SamTrans’ express buses will be caught in the tangle of traffic. That wasn’t lost on rider Orlando Mendoza, who drove from his home in Foster City to San Bruno BART and took the train to Embarcadero Station before the FCX bus started running.

“This is about the same amount of time,” he said. “Maybe a little longer on the way home.”

But at $6.25 for a round trip, it’s cheaper than other forms of mass transit, Mendoza said. And it beats circling a BART lot in search of parking —or sitting behind the wheel of a car that’s not moving.

Rachel Swan is a San Francisco Chronicle staff writer. Email: rswan@sfchronicle.com Twitter: @rachelswan