No one was seriously injured in the 8:15 p.m. accident, which occurred just yards from where crews were repairing a water main between Bishop and Fort streets.

There were no passengers on the Royal Star bus, said police Lt. Robert Green.

The bus driver, who may have had a heart attack or seizure before the crash, was in fair condition last night.

The driver of the car was in stable condition; his wife suffered minor injuries. Their sons were not seriously injured.

Green said it was a family of tourists.

The accident occurred as crews from Grace Pacific were waiting for the water main repairs to be completed so they could repave the road. Robert Willis, a truck driver with Grace Pacific, said he first thought the tour bus was a runaway vehicle.

"When I looked up, it never look like it had a driver. When I got to the bus, I didn't see anybody in the driver's seat. But when I looked in the window, I saw he was on the floor," Willis said. "I thought the bus went by itself. I said, 'The bus jumped in gear and went by itself.'"

Willis said the bus was leaving the Aloha Tower area when it crossed the east-bound lanes of Nimitz, went over a grass median and struck the silver Chrys ler 300.

At the time, there was only one west-bound lane open because of the pipe repairs.

"The cars were all stopped," Willis said. "The lanes were coned off and there was only one lane so he was stuck in the traffic. He had nowhere to go."

Willis helped the two boys and the woman out of the car, but he left the car's driver for paramedics because the man was wavering from consciousness to unconsciousness.

Willis and others pried the bus door open, turned off the engine and locked the brake.

The bus came to a stop against the parking structure of the Topa Financial Center, formerly the Amfac building.

Meanwhile, repair work on the water main was completed last night, officials said.

Two ewabound lanes that were closed at 9 p.m. Wednesday were reopened today at 2:30 a.m.

The break occurred at about 9 p.m. Wednesday under the right lane of Nimitz fronting Walker Park between Bishop and Fort streets. Police closed all four west-bound lanes for several hours until crews arrived to fix the 12-inch main.

Crews had to dig up a portion of the road to reach the break, forcing the shutdown of two right lanes on Nimitz.

Water service was restored to all customers by early yesterday morning, Board of Water Supply spokeswoman Wanda Yamane said.

"Water service was out probably a couple of hours in the early morning when most people were sleeping. That was because we had to close a lot of valves when we're trying to ascertain exactly what the damage was and where the broken pipe was located," Yamane said.