The California Highway Patrol says several crashes happened at the onramp on Jensen Avenue just before 10 p.m. A tow truck was responding to one of them when the driver was fatally hit.
Officers say the driver was halfway done loading up a white compact car when another vehicle collided with them.
Tow truck driver killed in Highway 99 crash near Calwa
About a dozen CHP officers responded to the scene, and officers say the onramp near the Highway 99 and Highway 41 interchange will be closed for several hours.
Authorities say the driver at the scene of the accident is in the CHP's rotational list for towing, and officers appeared to be familiar with the victim.
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