A man traveling southbound in the northbound lanes of Interstate 5 in Carlsbad on Monday collided with another vehicle, causing serious injuries to himself and another driver, California Highway Patrol officials said.

CHP officer Stephany Perez said the crash was reported on the highway near Carmel Valley Road around 8:15 p.m.

The incident began when a 38-year-old man in a Toyota Prius crashed head-on into a Toyota RAV4 driven by a 37-year-old man driven by the wrong-way driver, Perez said.

Two men from Carlsbad were taken to the hospital, Perez said.

Investigators said they are investigating whether drugs or alcohol were factors in the crash.

No other information was immediately available.

Police asked anyone with information about the crash to call the CHP office at (858) 293-6000.