REDWOOD CITY, San Mateo County, Calif., Sept. 23, 2026 — A three-vehicle crash left at least one person with minor injuries on Tuesday afternoon, September 22, on northbound US-101 near Woodside Road in Redwood City. The California Highway Patrol said the collision blocked a lane and prompted a request for an ambulance.
According to CHP radio traffic, a vehicle was first reported stopped in the number one lane shortly before 2 p.m. Officers arrived within minutes and confirmed a three-vehicle collision, requesting paramedics to the scene. They initially logged the crash as an unknown-injury collision before upgrading it to a minor-injury crash.
Medical personnel evaluated at least one party at the scene, and the San Mateo County Sheriff's Office was notified of the ambulance request, per dispatch logs. One of the vehicles involved was later moved to a nearby towing yard, CHP records show. It's unclear how many people were in each vehicle or whether anyone else was hurt.
Freeway service patrol units cleared the vehicles from the roadway by midafternoon, according to CHP notifications. The extent of injuries and the cause of the crash remain under investigation.
We hope those who were hurt recover fully and quickly.
Why Multi-Vehicle Crashes Cluster Near Freeway Interchanges
Stretches of freeway near major cross streets, like where US-101 meets Woodside Road, see more crashes than open highway sections because traffic patterns change fast in a short space. Drivers merging on or off the freeway must slow down, change lanes, and watch for exiting or entering vehicles all at once, and that mix of speeds is where a single stopped or slowing car can trigger a chain-reaction collision.
Distraction and following too closely tend to matter more in these zones than raw speed. When one driver brakes suddenly for an exit or a slowdown ahead, a driver behind who isn't leaving enough space, or who glances at a phone for even a second, often can't react in time. That's frequently how a two-car incident becomes a three-vehicle pileup.
According to the National Highway Traffic Safety Administration, an estimated 6,138,359 police-reported traffic crashes occurred in 2023. A meaningful share of those happen in interchange areas precisely because merging and lane-changing multiply the number of vehicles interacting in tight quarters at once.
Frequently Asked Questions
Do weather or road conditions play a role in freeway crashes like this?
Wet pavement, glare, or debris can reduce traction and visibility, but even on a clear, dry day, heavy merging traffic near an interchange raises the chance of a rear-end or multi-vehicle crash.
What should someone do right after being in a multi-vehicle crash?
Move to a safe location if possible, call 911, and wait for officers to document the scene. Getting checked by paramedics even for minor injuries is a good idea, since some injuries don't show symptoms right away.
Where do most freeway crashes tend to happen?
Crashes concentrate near on-ramps, off-ramps, and interchanges, where vehicles are merging, slowing, or changing lanes in close proximity to one another.
What to Do After a Car Accident in Redwood City, CA
If you're involved in a freeway crash in Redwood City, try to move to the shoulder or a safe area if your vehicle is drivable, and turn on hazard lights. Call 911 to report the collision and request medical help if anyone feels hurt, even if injuries seem minor at first.
Stay with your vehicle unless it's unsafe to do so, and wait for CHP officers to arrive and document the scene. Exchange information with other drivers involved, and consider seeking a medical evaluation within a day or two of the crash, since whiplash and other soft-tissue injuries can take time to appear.
