A woman was in critical condition and two children in serious condition after their bicycle was struck head-on by a car on Kamehameha Highway near Ke Waena Road on O'ahu's North Shore just after 8 a.m. yesterday.

According to Honolulu police, a 1991 Nissan sedan driven by a 44-year-old woman from Hale'iwa was heading west on the two-lane highway when it veered to the right and hit the bicycle, which was headed east in the adjacent bike lane.

The bicyclist, identified only as a caucasian woman, was thrown from the bicycle, hit the car's windshield and rolled onto the shoulder of the highway, police said. The two children, who were riding in a two-wheel trailer attached to the back of the bike, were pushed along with the bike for 80 feet until the car came to a complete stop.

The woman on the bicycle was taken to a hospital with critical head injuries. The two children, ages 5 and 3, were taken to the same hospital in serious condition, police said.

Off-duty lifeguard Dave Yester was running on the beach and came upon the accident just after it happened. He said a lifeguard captain at Rock Piles was working on one of the boys, who appeared to have a broken leg.

"I assisted the firefighters," he said. "They had just gotten there. I helped put people in the ambulance and helped give them oxygen. I just helped the firefighters. They had it under control.

"The mom was definitely the most serious," Yester said. "Her forehead was split. I've been a lifeguard for 20 years and you know when it's serious — and she was serious.

"I pray for her."

The accident occurred between Sunset Beach Elementary School and Pupukea Beach Park.

People at the accident site shortly afterward said there were no skidmarks, as if the car had run directly into the bicycle.

People at the scene said the smaller child was walking around, and when firefighters placed the woman and other boy on bodyboards to move them into the ambulance, he lay down on a board next to them.

Late yesterday, the mangled bicycle and trailer remained near the accident scene, behind a lifeguard station. Bits of broken glass littered the roadway.

People in the area said that motorists often speed and pass recklessly on the highway.

They also said the woman was hit when she was on the small portion of bike path that was really on the highway.

For much of its length through Sunset Beach, the bike path is separated from the road, but they merge just before Sunset Beach Christian School.

Residents said the woman and children were seen riding in the area almost every day.

It's been a dangerous year on O'ahu's roads, with 17 people killed in vehicular accidents so far. That compares with nine at this time last year.

Yesterday's North Shore accident came two days after four people died in two separate crashes on O'ahu that prompted police to appeal for caution.

This wasn't the first serious crash involving a bicyclist on the North Shore this year.

A 50-year-old man was killed Jan. 3 after his bicycle collided head-on with a car on Kamehameha Highway near the Turtle Bay Resort.