HONOLULU -- Police released a tour-bus driver involved in Monday's fatal crash on Oahu's Windward side, pending further investigation.

Officers arrested Steve Oshiro on Monday night on negligent homicide charges after he refused to submit to a blood-alcohol test.

Bus company Roberts Hawaii said it has a company policy to test its drivers after any collision. However, the company said it would not comment on the case because of the ongoing investigation.

Oshiro was at the wheel of a Roberts Hawaii motor coach when police said it drifted into oncoming traffic on Kamehameha Highway; slammed into a black SUV, hit a rock wall, then a house. The crash happened a day after Oshiro celebrated hit 49th birthday.

Corey Voss, 42, the SUV driver died at the scene. (Read: Co-workers Stunned By Loss)

"We are very, very sorry this accident happened, and we're sorry for the Voss family's loss," said Robert Moore of Roberts Hawaii.

Police said speed was not a factor, but they don't know if drugs or alcohol were involved because Oshiro refused to be tested.

"Our policy is to test the driver after every accident," Moore said.

Moore would not say if Oshiro was tested.

Police said they want to know if the company did it's own testing.

A check of Oshiro's driving record showed violations in 2001 for making a right turn on a red light and failing to stop for a pedestrian.

Although Roberts Hawaii wouldn't say how long Oshiro's worked there, they did say that he was hired after that violation.

The Department of Transportation normally gets involved in crashes involving commercial vehicles.

"We did check the driver's records and he did have the proper commercial driver's license as well as required medical certification. So if HPD (Honolulu Police Department) asks us to get involved, we'll check the truck for any mechanical failure and we'll hand over the findings to HPD as part of their investigation," DOT spokesman Scott Ishikawa said.

Roberts Hawaii said its dispatchers and supervisors are trained on drug-use recognition. Roberts Hawaii said that nothing usual was noticed on Monday.