A veteran bus driver making his last trip of the day was arrested on suspicion of driving under the influence Thursday after worried passengers made a 911 call about his erratic driving.

Police also arrested Searle Pestana, 61, on suspicion of violating the state's open alcohol container law.

Officials with TheBus said passengers called 911 after the bus scraped a branch along its right side. He was arrested at 7:30 p.m. at Kalaniana'ole Highway and Mekia Street in Waimanalo.

Honolulu police spokesman Maj. Alan Bluemke last night declined to release Pestana's blood-alcohol level.

"This is something we're deeply embarrassed about," said Roger Morton, O'ahu Transit Services Inc. president and general manager. "We want to promote highway and pedestrian safety. Any time we have an incident like this, it is shocking to us, and it's something we sincerely regret. We take this very seriously."

Pestana, who has been a bus driver for 36 years, has been suspended without pay, pending an investigation, Morton said.

"It's a multiple rule violation," Morton said. "We'll go through the process. This is the most egregious case in terms of substance abuse."

This is only the third time a bus driver has been investigated for driving under the influence, Morton said.

Morton also would not release the bus driver's blood-alcohol level at the time of the arrest. Pestana was driving on his regular route.

Pestana previously was charged in 2002 with DUI while he was not on duty for TheBus, Morton said. He was allowed to continue driving because state law at that time didn't require a mandatory one-year suspension of his commercial driver's license.

Current law mandates the suspension.

"Typically, a single event would be a career-stopping event," Morton said.

During the past three years, TheBus has administered 689 random alcohol screenings to its 1,600 drivers and maintenance workers. Alcohol was not detected in any of the 501 bus drivers tested, but three of the 188 maintenance workers tested were found to have alcohol in their system.

A positive alcohol test means a mandatory 30-day suspension without pay and counseling with a substance abuse professional, Morton said.

"We don't condone driving with any alcohol," Morton said. "Safety is a paramount rule. We consider anyone over a .02 (blood-alcohol level) unfit for duty and impaired with a .04."

State law has set a limit of .08 blood-alcohol level to be considered driving under the influence.

Pestana's record with TheBus before the Thursday incident was generally good in terms of safety, attendance and customer service, Morton said.