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CASTAIC, Los Angeles County, Calif., Oct. 26, 2026 — A multi-vehicle pileup involving a U-Haul truck and a semi tractor-trailer shut down lanes on southbound Interstate 5 Sunday night, October 25, just north of Templin Highway, the California Highway Patrol said. Several vehicles were involved and injuries were reported at the scene.
According to dispatch logs, the crash began as a chain-reaction collision involving a sedan and a diesel truck shortly before 7:50 p.m., blocking the middle lane. Within minutes, additional vehicles were reported involved, including a gray Toyota Camry and a semi tractor-trailer, and a U-Haul truck collision blocking a second lane. Authorities said all lanes of southbound I-5 were stopped by around 8 p.m. as crews worked to clear the scene.
The call was upgraded from a collision with unknown injuries to one requiring an ambulance response. By about 8:09 p.m., a vehicle that had been blocking traffic was pushed onto the shoulder.
The cause of the initial collision remains under review. We hope those who were hurt recover quickly.
More on Crashes in Castaic, CA
This truck crash happened on Interstate 5 in Castaic, CA. We cover crashes across Los Angeles County as they're reported, and you can browse the latest in our Los Angeles County accident reports.
Frequently Asked Questions
Does driver fatigue play a role in truck crashes?
It can. Fatigue slows reaction time and is a factor investigators routinely examine in commercial truck crashes, especially those happening at night or after long stretches of highway driving.
What should I do after a crash involving a commercial truck?
Call 911, move to a safe area if possible, and seek medical evaluation even if injuries seem minor. Get a copy of the police report and document the scene with photos if you're able.
Why do big rigs need more distance to stop than cars?
Loaded trucks can weigh tens of thousands of pounds more than passenger vehicles, which means their brakes need far more distance and time to bring them to a stop, especially at highway speeds.
What makes truck crashes more dangerous than typical car accidents?
The size and weight difference between a semi and a passenger vehicle means collisions often cause more serious damage and injury, even at moderate speeds.
What to Do After a Truck Crash in Castaic, CA
If you're involved in or witness a highway pileup like this one, your safety comes first. Stay in your vehicle with your seatbelt on if you're stopped in traffic and it's not safe to exit, and turn on hazard lights to alert other drivers. If you can safely move to the shoulder, do so. Once you're out of danger, check yourself and passengers for injuries and call for emergency help right away.
Afterward, follow up with a doctor even if you feel fine. Adrenaline can mask pain from whiplash, internal injuries, or other trauma that shows up hours or days later. Keep records of any medical visits and vehicle damage, and request the official collision report once it's available from the California Highway Patrol. Residents of Castaic affected by highway backups or involved in the crash can also check local traffic advisories for updates on road conditions.
