SAN MATEO, San Mateo County, Calif., Oct. 16, 2026 — Three vehicles collided on Thursday morning, October 15, on northbound US-101 near Poplar Avenue in San Mateo. The crash left at least one person with injuries described as minor and blocked two right lanes of the freeway.
The California Highway Patrol said the collision was first reported shortly before 11 a.m. and involved a black Hyundai Elantra and at least one other vehicle. A blue Mazda was also identified at the scene. The agency's initial call classified the crash as a collision with unknown injuries before it was updated to a report of minor injuries.
An ambulance was requested for the Hyundai driver, and the San Mateo County Sheriff's Office was also notified. A Freeway Service Patrol unit responded and later towed a vehicle from the scene before clearing its own incident. One driver was reported transferred into the ambulance at the scene.
The two right lanes of northbound US-101 were blocked for a period while crews worked the scene and arranged a tow, CHP records show. The log does not identify how many people were in each vehicle or specify the full extent of injuries. The cause of the crash has not been released and remains under investigation.
We hope everyone who was hurt makes a full and speedy recovery.
Local Crash Information for San Mateo, CA
The multi-vehicle crash was reported at US-101 and Poplar Avenue in San Mateo. For more crash news from the area, see our latest San Mateo County crash news.
Frequently Asked Questions
Are secondary crashes common after an initial wreck like this one?
Yes. When lanes stay blocked on a busy freeway, drivers approaching the backup usually have little time to react, and rear-end or sideswipe crashes can follow the first one.
What makes a three-vehicle crash harder to sort out than a two-car crash?
With more vehicles involved, investigators have to reconstruct the order of impacts, figure out which car struck which, and interview more drivers and witnesses before they can determine fault.
What usually triggers a chain-reaction crash on a freeway?
Sudden braking, a stalled or slow vehicle, lane changes, or reduced visibility can all cause one car to strike another, and that first impact can pull in additional vehicles before traffic can slow down.
What to Do After a Multi-Vehicle Crash in San Mateo, CA
If you're involved in a multi-car crash on the freeway, try to move to the shoulder if your vehicle is drivable and it's safe to do so. Turn on hazard lights and stay inside the vehicle if you're stopped in a travel lane, since stepping out near moving traffic is dangerous. Call 911 to report the crash and request medical help even if injuries seem minor, since some symptoms show up hours later. Exchange information with other drivers when possible, and if CHP or local officers respond, get a copy of the report number for your records. Afterward, see a doctor for a checkup and keep track of any paperwork, photos, or witness contacts related to the crash.
