San Mateo County, CA — December 5, 2025, two people were injured due to a truck accident at approximately 3:30 p.m. along State Highway 92, San Mateo Road.

According to authorities, two people were traveling in a passenger vehicle on San Mateo Road in the vicinity west of State Highway 35 when the accident took place.

Officials indicate that, for as yet unknown reasons, a collision occurred between that vehicle and an 18-wheeler occupied by two people. The truck apparently overturned over the course of the accident.

Two people from a single-vehicle—though reports do not specify which—reportedly sustained moderate injuries over the course of the accident. They were transported to an area medical facility by EMS in order to receive necessary treatment.

Additional details pertaining to this incident—including the identities of the victims—are not available at this point in time. The investigation is currently ongoing.

Commentary by Attorney Michael Grossman

When an 18-wheeler ends up overturned in a two-vehicle crash, it raises serious questions about control, speed, and maneuvering—especially on a highway like San Mateo Road, where curves, grades, and limited escape space can magnify even small driving errors.

The reports don’t yet say which vehicle’s occupants were injured, or how the two vehicles came into conflict. But regardless of who was more seriously hurt, an overturned semi means this wasn’t a minor scrape—it was a high-energy event that likely involved a loss of control, evasive action, or both. In situations like this, investigators need to figure out whether the truck tipped while reacting to another vehicle, or whether the truck itself triggered the crash by drifting out of its lane, braking too late, or misjudging a curve.

Overturned trucks also raise mechanical and cargo-related questions. Was the trailer loaded properly? A shifting or imbalanced load can make a rig unstable, especially on winding roads or in sudden braking scenarios. In cases I’ve handled, an overloaded trailer or a poorly secured shipment turned a manageable maneuver into a rollover because the driver was set up to fail long before they took the wheel.

It’s also important to examine the truck’s speed relative to the roadway. Highway 92 west of Highway 35 isn’t flat, straight interstate—it’s a tighter, more technical drive, and professional drivers are expected to adjust accordingly. If the truck was traveling too fast for the curve or carrying too much momentum downhill, that might explain how it ended up on its side.

Finally, a rollover like this demands a look at driver qualification and training. Was the driver familiar with the route? Were both occupants in the cab authorized and qualified to be there? These are the kinds of details that don’t usually show up in early reports, but they matter when assessing responsibility.

Key Takeaways:

• An overturned 18-wheeler suggests a high-energy impact or loss of control that must be investigated carefully.
• Cargo balance, speed, and road geometry are all potential contributing factors in truck rollover scenarios.
• It’s unclear whether the truck caused the collision or was reacting to the other vehicle—dash cam footage and ECM data can help determine that.
• Investigators should examine whether the truck’s speed and handling matched the demands of the roadway.
• Driver training, route familiarity, and load securement practices may all be relevant in understanding how the crash occurred.