A driver who police said fell asleep while driving crashed his truck in Nanakuli, injuring himself and a passenger, and clogging morning traffic on Farrington Highway.

At about 1:20 a.m., police said a 21-year-old Waipahu man was driving westbound on Farrington Highway in a truck with a 27-year-old Honolulu man when the driver fell asleep at the wheel. The vehicle veered off the road and into the right shoulder, slamming into a wooden utility pole, about 90 feet east of Maaloa Road.

Police said the passenger, who was not wearing a seat belt, was ejected from the vehicle. Emergency Medical Services paramedics treated and transported him to a hospital in critical condition. Paramedics transported the driver to a hospital in serious condition.

Police said speed, alcohol or drugs were not involved, and the investigation is ongoing.

The crash led to lane closures on Farrington Highway, and police to temporarily open the emergency bypass road at Paakea and Hakimo roads and Paakea and Lualualei Naval roads to alleviate morning traffic. The bypass road was opened from about 6:30 a.m. to 7:50 a.m.

A power outage affected nine customers in the area due to the damaged pole. Shannon Tangonan, spokeswoman of Hawaiian Electric Co., said a crew was sent to replace the pole and the work had been completed by the afternoon.