REDWOOD CITY, San Mateo County, Calif., Sept. 21, 2026 — A vehicle rolled onto its roof on Sunday night, September 20, on northbound US-101 near the Woodside Road on-ramp in Redwood City, according to the California Highway Patrol. The agency initially logged the crash as an injury collision and later upgraded it to a major-injury crash.
Officials said a car was merging onto northbound US-101 from Woodside Road when it overturned and came to rest on its roof on the right shoulder. Two other vehicles were also reported on the shoulder nearby, though it was not immediately clear how they were involved.
Witnesses reported seeing occupants get out of the overturned car and run through traffic lanes. One caller described three men getting out of the vehicle, and another report described a person running from the scene toward Broadway. It was not confirmed whether that individual was involved in the crash or a bystander. Paramedics were requested to the scene for injuries, and the extent of those injuries has not been released.
Redwood City police and San Mateo County sheriff's units responded along with CHP officers to manage traffic. The Woodside Road on-ramp and off-ramp were intermittently blocked for several hours overnight while crews worked the scene and a tow truck removed the overturned vehicle, which was reported to be a Toyota. Ramps were reported reopened by around 12:40 a.m.
The California Highway Patrol has not released a cause for the rollover. The crash remains under investigation.
Our thoughts are with those who were injured, and we wish them a full recovery.
Where Rollover Crashes on Freeway On-Ramps Tend to Happen
Rollovers cluster in a few predictable settings: freeway on-ramps and interchanges, rural undivided highways, and curves where a vehicle's speed does not match the road's geometry. On-ramps like the one where this crash occurred create a specific risk because drivers are accelerating and changing lanes at the same time they are merging into fast-moving traffic, leaving less room to correct if a vehicle drifts onto a shoulder or shallow ditch.
Any sudden yaw at highway speed, whether from an overcorrection, a tire failure, or a hard swerve, can trip a vehicle sideways and start a roll, especially in taller vehicles with a higher center of gravity. Shoulders and ramp edges usually have a drop-off or uneven pavement that can catch a tire and start that same sideways slide.
According to the National Highway Traffic Safety Administration, 20 percent of passenger-car occupant fatalities occurred in vehicles that rolled over in 2023. Interchange ramps and merge points show up sometimes in rollover data because they combine speed changes, lane changes, and limited shoulder width in one short stretch of road.
Frequently Asked Questions
What causes a vehicle to roll over?
Rollovers usually start with a sideways skid or yaw, usually from a sharp steering correction, a tire blowout, or striking a curb or soft shoulder at speed. Once a vehicle's tires lose grip and it begins sliding sideways, the sudden change in direction can trip it into a roll.
Are rollovers more common on certain types of roads?
Yes. They occur more frequently on ramps, curves, and undivided rural highways where speeds are higher, and there is less room to recover from a lane departure than on a straight urban street.
What injuries are common in rollover crashes?
Occupants can be thrown against the roof, doors, or windows as the vehicle turns over, leading to head, neck, and spinal injuries. Unbelted occupants face a much higher risk of being ejected.
How can drivers reduce rollover risk?
Wearing a seat belt, avoiding sharp last-second steering corrections, and slowing down before curves or ramps all reduce the chance that a skid turns into a rollover.
What to Do After a Rollover Crash in Redwood City, CA
If you're involved in or witness a rollover, call 911 right away and, if it's safe, move away from traffic lanes rather than standing near the roadway. Even if you feel fine, get checked by a medical provider soon after, since injuries from a rollover, especially to the head, neck, or back, are not always obvious right away.
Ask for a copy of the CHP incident number and note which agency responded, since rollovers on state highways in Redwood City are typically handled by the California Highway Patrol with support from local police and fire crews. If your vehicle was towed, get the tow company's name and location from the responding officer before leaving the scene.
