CARLSBAD, Calif. -- Three people were injured Wednesday, one seriously, when a delivery truck driven by a fatigued young man veered off Interstate 5 near Agua Hedionda Lagoon and smashed into a big rig parked on the shoulder, authorities reported.

Joshua Hayden, 21, was heading south at about 60 mph when he nodded off behind the wheel of the Chevrolet bobtail truck near Tamarack Avenue in Carlsbad around 7:15 a.m., according to California Highway Patrol public affairs Officer Eric Newbury.

The vehicle drifted off the freeway and plowed into the back of a tractor-trailer whose driver, 23-year-old Andy Rodriguez of North Hollywood, had pulled over to make a cell phone call moments earlier, the officer said.

The crash left left a passenger in Hayden's truck, 28-year-old Alisa Harvaph of San Diego, with serious leg trauma and the two truck drivers with minor injuries, Newbury said.

Medics took Harvaph and the two men to Scripps Memorial Hospital La Jolla.

Three of the freeway's four lanes were blocked for a time by the damaged trucks, debris and emergency vehicles, creating gridlock that reached El Camino Real and State Route 78 in Oceanside.

A county hazardous-materials team was called to clean up about 15 gallons of spilled diesel fuel, the CHP reported.

By 9:45 a.m., all but one of the lanes was reopened, and the fourth was back in service by shortly before 10:30 a.m.

Investigators determined that Hayden, a San Diego resident, had fallen asleep at the wheel just prior to the accident, Newbury said.