OAKLAND (CBS SF) — A driver who left his vehicle after an early Wednesday morning crash on Interstate Highway 580 was fatally struck by another vehicle, shutting down lanes and creating a massive backup, authorities said.

The California Highway Patrol said the crash was first reported at 4:06 a.m. on the westbound side of I-580 just east of Lakeshore Ave. The fatal crash involved three vehicles.

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CHP Sgt. Alex Edmon told KPIX 5 that a driver of a Mercedes lost control of their vehicle and spun out in the westbound lanes as heavy rains fell in the area. A pickup truck then collided with the Mercedes.

Both drivers got out of their vehicles, he said. The driver of the pickup truck walked around his vehicle to the passenger side and was fatally struck by a Honda sedan.

The force of the impact hurled the driver’s body into the eastbound lanes. He was identified by the Alameda County Coroner’s Office as 35-year-old Daniel Contreras of San Jose.

“Anytime you’re in a collision, your number one attempt should be to drive to either the right-hand shoulder or the center median. Regardless of the amount of damage you can still make that attempt and your vehicle will probably still move,” said Edmon. “If you’re unable to do that, you need to remain in your car with your seatbelt on. That’s the safest place for you to be, and then call 911 and let them know where you are and when can get to you and make the scene safe for you.”

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But staying in the car may not be most drivers’ first instinct. People KPIX spoke with Wednesday said it would feel strange after an accident to just sit there and do nothing.

“I would want to get out and make sure that nobody got, you know, a concussion or got hurt,” said Berkeley resident Michaelah Ivie.

Oakland resident Chris Carrier said that would also be his reaction. “Get out of the car and see what the damage is, you know? I’d get out and look.”

It may seem intuitive to get out of your car after an accident, but if you’re still in the freeway lanes, don’t do it! The CHP says cars approaching may not be able to stop in time and even standing behind your disabled vehicle may not be enough protection to save your life. It didn’t in Wednesday’s crash.

All lanes on the busy freeway were shut down. Both directions and all lanes were reopened by 5:47 a.m. While the lanes were closed, traffic was taken off the highway at Grand Ave.

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Motorists were advised to expect delays and to use alternate routes.