The 49-year-old tour bus driver involved in a fatal, head-on collision in Kahalu'u on Monday afternoon had rear-ended a city bus that morning.

In addition, tour passengers who were on a Roberts Hawaii bus driven by Steve Oshiro at some point during the day before the fatal crash said he was driving erratically and have turned over "visual evidence," according to police sources who did not want to be identified because the investigation is ongoing.

At 6:05 a.m. Monday, 8 1/2 hours before the fatal collision, the tour bus driven by Oshiro hit a city bus in the area of Punahou and Beretania streets, causing minor damage, according to Michelle Kennedy, manager of customer communications for O'ahu Transit Services.

After the morning collision, Oshiro returned to Roberts Hawaii's headquarters to report a "minor accident," according to Sam Shenkus, spokeswoman for Roberts Hawaii. The tour bus had no passengers when it struck the city bus and no one was injured in the collision, the company said.

Oshiro was terminated from his job yesterday because he refused the company's request to take a drug and alcohol test, according to a statement released by Roberts Hawaii.

Oshiro refused a field sobriety test at the scene of the fatal accident and later refused a blood test at Castle Medical Center. He was arrested on suspicion of negligent homicide in the third degree, a misdemeanor, and released.

The collision on Kamehameha Highway claimed the life of Corey Voss, 41, of Kane'ohe. Oshiro crossed the center line and struck Voss' sport utility vehicle before crashing into a house at 2:30 p.m.

Refusing to submit to a field sobriety test following an accident can result in the loss of a driver's license, personal or commercial, for up to a year, according to the state Department of Transportation.

"Upon learning he was released by the police, Roberts Hawaii asked Mr. Oshiro to submit to a drug and alcohol analysis as required by company policies and federal and state transportation regulations," said Deems Narimatsu, senior vice president for Roberts Hawaii. "Mr. Oshiro's attorney refused to allow the test. Roberts Hawaii's procedures and policies are clear and comprehensive in this matter and Mr. Oshiro was terminated."

Because Oshiro holds a commercial driver's license, Roberts Hawaii is obligated by federal law to test him for intoxicants within eight hours of a fatal crash or the company risks fines and penalties.

Two calls seeking comment from Oshiro's attorney, William Harrison, were not returned yesterday. Attempts to contact Oshiro were unsuccessful.

The company declined to release the route Oshiro was driving and to provide the number of passengers he transported throughout the day, or when they boarded and disembarked from the bus. However, the company confirmed that Oshiro did drive passengers back and forth between the times of the two accidents.

Every day, Roberts Hawaii has more than 750 vehicles on the road transporting tourists, residents and schoolchildren, according to a statement released earlier this week by the company.

Passengers who at one point rode the tour bus have turned over "visual evidence" of erratic driving and made statements to investigators, the police sources said.

Honolulu police Capt. Frank Fujii yesterday said the department is investigating both the early morning accident and the fatal crash. He declined further comment, citing an ongoing criminal investigation.

Police say they will attempt to contact a Windward O'ahu resident who contacted The Advertiser after the crash, saying he followed a Roberts Hawaii tour bus from Ha'iku Road to 'Ahuimanu Place and noticed the driver "driving very slowly, varying speed up and down, and (weaving) all over the road." The resident did not want to be identified because he fears retribution from the driver.

Other cars were "stacking up" behind the bus, the resident said, and at 'Ahuimanu Place he decided to drive away from the tour bus by passing several cars and the bus. The resident said he looked back at the driver.

Upon seeing the driver's face on television that evening, the resident said he made the connection.

Oshiro — who turned 49 the day before the two crashes, according to police — has not been charged in the case.

Reach Peter Boylan at pboylan@honoluluadvertiser.com.