One man was critically injured and five other people hospitalized in serious condition after two cars crashed head-on on Farrington Highway in Nanakuli Saturday morning. The accident may have been caused when a driver fell asleep.

The crash occurred about 9:20 a.m. in front of Ka Waihona o Ka Na‘auao Public Charter School, formerly the campus of Nanaikapono Elementary School.

A Waianae woman, 18, who was driving west toward Makaha in a gray Chevrolet Trailblazer sport utility vehicle, told officers that she fell asleep at the wheel and crossed the center line, said Lt. Robert Towne of the police Traffic Division. The SUV collided with a white compact sedan headed toward town, he said.

The driver of the sedan, a 22-year-old Waianae man, was taken by ambulance to the Queen’s Medical Center in critical condition, he said.

The driver of the SUV was taken to the hospital in serious condition, as was a male passenger, 17, in the sedan and three girls in the SUV, ages 12, 5 and 2, a city Department of Emergency Services district chief said.

All the injured are from Waianae, police said.

The front driver’s side of the sedan was caved in by the impact.

There were no obvious signs that alcohol was a factor in the crash, Towne said.

For several hours after the accident, only one eastbound lane of Farrington was open in the area, while westbound traffic was rerouted to Nanakuli Avenue. All lanes were reopened shortly after noon.

An irate family member who arrived at the scene had to be restrained with a Taser and was arrested, police said.

The Maili man, 38, was treated for what appeared to be minor injuries, then arrested on suspicion of harassing a police officer, a petty misdemeanor. He was released after posting $250 bail.