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SAN MARCOS, San Diego County, Calif., Oct. 1, 2026 — A multi-vehicle crash with injuries shut down a lane of westbound State Route 78 near Nordahl Road on Wednesday morning, September 30, according to the California Highway Patrol. The wreck involved four vehicles and left at least one person hurt.
The crash was first reported as a two-vehicle collision involving a white SUV and a white van, the CHP log shows. Within minutes, dispatchers received reports that the incident had grown to involve four vehicles, with the number one lane blocked and airbags deployed in at least one vehicle.
Emergency crews were sent to the scene, and fire personnel responded alongside CHP units. The California Highway Patrol later reclassified the call from a traffic collision with a vehicle possibly entering traffic to a confirmed minor-injury crash. A tow truck was requested to help clear vehicles blocking the roadway.
Freeway Service Patrol units assisted at the scene and had closed out their involvement by mid-morning, dispatch logs indicate.
The crash remains under investigation. We wish those injured a speedy recovery.
Multi-Vehicle Pileups and the Toll Beyond Passenger Cars
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. That figure includes pedestrians, cyclists, motorcyclists and occupants of larger vehicles like vans and trucks, all of whom can end up part of a chain-reaction crash on a freeway.
Multi-vehicle collisions often start small, a single rear-end or lane-change crash, before additional vehicles arrive too fast to stop and add themselves to the pileup. Work vans, SUVs and passenger cars all respond differently in a crash depending on their size and structure, which is part of why investigators look closely at vehicle types involved when sorting out how a chain-reaction crash unfolded.
Highway chain-reaction crashes also tend to concentrate at spots where traffic merges, narrows or slows unexpectedly, such as near interchanges and off-ramps. Response to these scenes typically requires coordinating fire, tow and traffic-control resources simultaneously, since clearing blocked lanes fast is part of preventing the pileup from growing further.
Frequently Asked Questions
How can drivers avoid getting caught in a pileup?
Leaving extra space ahead, watching traffic patterns well down the road, and slowing early when brake lights appear ahead can help drivers avoid getting pulled into a chain-reaction crash.
What should I do if I'm stopped near a crash on the highway?
Turn on hazard lights, stay buckled in if it's safe to remain in the vehicle, and move as far from traffic lanes as possible. Only exit the vehicle if staying inside poses a greater risk.
Why does following distance matter so much on freeways?
Shorter following distances leave less time to react when traffic ahead slows suddenly, which is a common way one crash becomes several.
How does fog or low visibility factor into these crashes?
Reduced visibility cuts the time drivers have to see slowed or stopped traffic ahead, which is why chain-reaction crashes often cluster during foggy or low-light conditions.
What to Do After a Multi-Vehicle Crash in San Marcos, CA
If you're involved in a multi-vehicle crash, move to a safe area if your vehicle is drivable and check on others nearby before anything else. Call 911 even for what seems like a minor crash, since injuries from airbag deployment or impact aren't always obvious right away.
Seek a medical evaluation even if you feel fine; adrenaline can mask pain from whiplash or soft-tissue injuries for hours. Exchange information with other drivers, take photos of the scene if it's safe to do so, and request a copy of the CHP report once it's available. Keep track of any symptoms that develop in the days after the crash.
