From new subway lines to rapid transit lanes and high-speed trains, California is undergoing a public transportation overhaul.
Now, a new proposal could reshape long-distance travel entirely, as Caltrans just announced it’s exploring the concept of high-speed buses capable of reaching up to 140 mph on freeways. The proposed statewide network would link major hubs such as Sacramento, the Bay Area, San Diego and L.A.
The system would use dedicated freeway lanes, purpose-built transit stations, and long-distance express services. Officials are also studying international examples, including Australia’s Adelaide O-Bahn busway and the Netherlands’ Superbus prototype, KCRA reported. The buses could cut the SF–L.A. trip to roughly three hours and 12 minutes.
How would Caltrans’ “bullet buses” work?
Since most highways are designed for speeds of up to about 85 mph, running significantly faster bus services would require major upgrades to roadway infrastructure and engineering.
Reaching those speeds safely would likely rely on a mix of dedicated lanes, specially engineered vehicles, and advanced safety technologies. These could include automated driving systems, improved braking performance, and vehicle-to-everything communication systems to help coordination and reduce risk at high speeds.
Potential corridors include Interstate 80, Interstate 5, and U.S. 101 as key interregional routes. State Route 99 was highlighted as a possible early candidate due to its direct links between major Central Valley cities such as Bakersfield, Fresno, Modesto, Stockton, and Sacramento.