SAN MATEO, San Mateo County, Calif., Sept. 22, 2026 — A two-vehicle crash left at least one person injured Monday morning, September 21, on northbound US-101 near State Route 92 in San Mateo, according to the California Highway Patrol. The collision blocked traffic lanes for roughly half an hour during the morning commute.
The California Highway Patrol said a red Toyota Camry and a gray Volvo sedan collided on northbound 101 just south of the Route 92 interchange. Initial radio traffic described uncertain lane positioning before the impact, though the exact sequence has not been detailed publicly.
An ambulance was requested at the scene, and the crash was logged as a minor-injury collision, per dispatch records. The report did not specify how many people were hurt or the extent of any injuries.
The crash blocked the express lane and the number one lane, backing up traffic before crews cleared the scene. A tow company was called to remove at least one of the vehicles. The California Highway Patrol's Freeway Service Patrol closed out its response to the incident by midmorning.
No further details on the cause have been released. The collision remains under review by the California Highway Patrol.
We wish those injured a full recovery.
Why a Highway Interchange Crash Like This Does So Much Damage
Crashes near freeway interchanges tend to be harder-hitting than typical fender-benders because of what's happening around them: vehicles merging, exiting, and changing speed all at once. When one driver slows to navigate a ramp, and another is still moving at highway speed, the gap in speed between the two vehicles, not just their individual speeds, determines how hard the impact is.
Interchanges also concentrate risk because they cram multiple decisions into a short stretch of road. Drivers are watching for exit signs, merging traffic, and lane markings simultaneously, which leaves less attention for any single hazard. That's part of why crash rates cluster at exits and interchange approaches rather than spreading evenly across a highway.
Modern vehicles are built to absorb impact at the front and rear through crumple zones, while the passenger cabin is reinforced to resist collapsing. But that design only works within limits. A car struck at an angle, or a car with a heavier or larger vehicle involved, usually sees more force transferred into the cabin, since the point of impact and the vehicle's built-in protection don't always line up. According to the Insurance Institute for Highway Safety, 17,008 motor-vehicle crash deaths occurred outside passenger vehicles in crashes involving passenger vehicles in 2023.
Frequently Asked Questions
Where do most traffic crashes happen?
A large share occurs at or near intersections, on-ramps, and interchanges, where vehicles merge, turn, or change speed in close proximity to one another.
What can drivers do to lower their crash risk?
Leaving extra following distance near ramps and interchanges, checking mirrors and blind spots before merging, and avoiding distractions during lane changes all reduce the split-second errors that cause many crashes.
What injuries commonly result from car crashes like this one?
Whiplash, soft-tissue injuries, and bruising from seatbelts or airbags are common in moderate-speed collisions. Some crashes also cause head or chest injuries, depending on the angle and force of impact.
What typically causes crashes at highway interchanges?
Common factors noted in early reports of this incident include following too closely, misjudging gaps while merging, sudden braking, and unclear lane positioning.
What to Do After a Car Crash in San Mateo, CA
If you're involved in a crash near a busy interchange, try to move to a safe location if the vehicle is drivable and turn on hazard lights to warn oncoming traffic. Call 911 to report injuries and request assistance, even if the damage looks minor at first glance.
Get checked by a medical professional as soon as possible. Some injuries, especially soft-tissue and whiplash-type injuries, don't show symptoms right away. Exchange information with the other driver, take photos of the vehicles and the surrounding roadway, and request a copy of the official crash report once it's available. Keeping records of any medical visits and repair estimates will help if you need to file an insurance claim later.
