CA: California’s latest transit dream: A bus from S.F. to L.A. that could hit 140 mph

With the future of high-speed rail uncertain, Caltrans has quietly begun studying a similar, if more audacious idea: buses that zip from San Francisco to Los Angeles at 140 miles per hour.

The bullet bus concept is still in its embryonic stage and comes with many challenges. First and foremost is the infrastructure. U.S. freeways could accommodate a transit vehicle traveling up to 85 miles per hour, Caltrans engineers posit, but anything beyond that presents risks for braking or maneuvering curves. A bus operating at breakneck speed would need a dedicated lane and a technologically advanced design, possibly with automated driving systems and highly precise reaction times, according to the agency’s senior transportation planner Mehdi Moeinaddini.

He wrote a preliminary report last year on the feasibility of a high-speed bus network, contending that the vehicles would make travel more efficient and display “technological ambition” if they ever came to fruition. However, Moeinaddini wrote, if the cost is daunting and the logistics are too complicated, “a more moderate target of 80—100 mph can serve as a practical and impactful alternative, still offering significant improvements over current standards.”

Tom Radulovich, a former BART board director and senior policy lead at the nonprofit Livable City, is at once fascinated by and skeptical of the high-speed bus pitch.

“Honestly, once you’ve gone through all the trouble of building all this infrastructure with the dedicated right-of-way, you may as well build rail,” Radulovich said. “It’s like when Elon Musk was goofing around with Tesla tunnels. At some point, you’ve just got an inferior version of a subway.”

But officials at Caltrans have described their still-hypothetical bus system as a supplement, rather than a replacement for high-speed rail. The agency’s feasibility studies manager, Ryan Snyder, has even proposed bus connections from high-speed rail’s current termini at Merced and Bakersfield, on the notion that it could take years for the train to reach job centers in San Francisco and Los Angeles.

“What if the first priority of our system were regional and interregional public transit?” Snyder asked during a May 13 Caltrans webinar about the freeway bus concept. He presented slides depicting a reimagined freeway with wide red lanes for buses. They would pull into stations along the shoulder, converting each interchange into a transfer point, Snyder said. He noted that developments in automated driving systems could allow the buses to mix with other freeway traffic, bringing down the capital costs.

Spokespeople at California High-Speed Rail Authority were not immediately available for comment.

For the time being, Caltrans staff emphasize that they will only move forward if they determine that high-speed buses are cost-effective and would improve transportation overall.

“The department’s long-term strategic vision accounts for cutting-edge innovation that will transform the transportation landscape and help our goal of improving quality of life for all Californians,” Caltrans spokesperson Christopher Clark wrote in a statement.

Ultimately, the bus lines that Caltrans researchers are contemplating could be more expansive than the high-speed rail map, potentially including Sacramento and large swaths of the Bay Area while also extending through the Central Valley, then south through Los Angeles and San Diego. Snyder floated Interstate 80, I-5, Highway 101 and State Route 99 as prospective routes.

State transportation officials are already planning to build express bus stations in San Diego and Contra Costa counties, Clark said, with more locations to come.

© 2026 the San Francisco Chronicle.
Visit www.sfchronicle.com.
Distributed by Tribune Content Agency, LLC.