About three-fourths of the nearly 400 accidents involving Oahu’s municipal garbage trucks over the past five years were determined by the city to be avoidable, including several in which a pedestrian or motorist was injured or killed, according to a Honolulu Star-Advertiser analysis of crash data.

The city’s own investigations of the accidents found that 7 of every 10, or 70 percent, were considered avoidable because the Department of Environmental Services drivers failed to take all reasonable precautions to prevent the collisions, the analysis shows.

The accident summaries compiled by the city indicated that most of the 271 avoidable incidents from 2009 through 2013 were minor, did not involve pedestrians or other motorists, and typically resulted in the striking of a mailbox, parked vehicle, tree or other object.

A driver in June 2013, for instance, forgot that he still had a trash container in his truck’s mechanical gripper and drove a block before striking a parked car.

But in about half a dozen incidents, pedestrians or motorists were struck under circumstances in which the city determined that its driver failed to take reasonable steps to prevent the accident, according to the data, obtained by the Star-Advertiser through a public records request.

One resulted in the death of an 83-year-old pedestrian who was hit in February 2013 as a garbage truck was reversing in an Aiea cul-de-sac, a maneuver for which the city has no policy, according to the records and a police accident report.

The 52-year-old male driver, who had 23 years of experience with the refuse division, told police he opted to reverse out of the cul-de-sac instead of turning around in it because that was easier to do, the Honolulu Police Department report showed.

But the driver, whose name was redacted from the report, said he didn’t see Pauline Ando when he checked the truck’s rear-view mirrors and its video monitor before backing up, according to the records.

After reversing, the driver spotted the 5-foot-5-inch woman, who was wearing a green shirt and khaki shorts, on the road partially under his truck and stopped the vehicle, city and police documents show. Ando died later at a hospital.

Police concluded that the driver committed second-degree negligent homicide, but prosecutors declined to pursue a case because of a lack of sufficient evidence to prove gross negligence, according to the HPD report.

Ando’s family members could not be reached for comment.

Garbage trucks are so large — many models easily top 40,000 pounds — and travel in such heavily populated neighborhoods that even the slightest mistake or period of inattention can result in significant damage, injury or death.

One study done more than a decade ago by a pedestrian safety group in New York found that garbage trucks were responsible for more fatalities per 100 million miles driven than any other type of vehicle in the region.

"The size of these vehicles and the dense environments they operate in make careful driving imperative," said Dan Galanis, epidemiologist for the Health Department’s Injury Prevention and Control Section.

The Star-Advertiser requested five years’ worth of crash data from the city after a February accident in which a 70-year-old female pedestrian was fatally struck by a municipal garbage truck while in a Kalihi crosswalk.

Her death came one year after Ando’s and 11 months after another pedestrian, 88, died from injuries suffered in a Nuuanu accident involving a private refuse truck.

Hawaii holds the dubious distinction of being the most dangerous place for pedestrians over 65.

Daniel Blower, a scientist at the University of Michigan’s Transportation Research Institute, said the city’s avoidable accident rate seems high but that he would need more details to better evaluate the data, including whether the severity of accidents is increasing and whether the reporting threshold has remained constant.

"If these guys are dinging mirrors, I wouldn’t be too concerned," Blower, whose expertise includes truck safety matters, wrote in an email to the Star-Advertiser. "If they are knocking down traffic signs, then I’d wonder what is going on."

Asked whether the city was satisfied with a 70 percent avoidable accident rate, Tim Houghton, the department’s deputy director, said his agency was unable to verify the Star-Advertiser’s calculations.

"It is important to note that the city operates its refuse trucks six days a week, covering over 25,000 refuse vehicle routes each year," Houghton wrote in an email. "The number of accidents involving these vehicles is relatively small in comparison, and many of the incidents involve relatively minor property damage."

On an annual basis, the avoidable accident rate peaked at 74 percent in 2011 and 2012 before dropping to 64 percent last year, according to the newspaper’s analysis.

When accidents result in injury or death, the potential costs to the city — and ultimately taxpayers — can be significant.

That was underscored recently when the City Council approved a $1.25 million settlement of a lawsuit brought by a pedestrian whose right foot was amputated after a 2012 incident.

A city garbage truck ran over Paula Harris’ foot as she was in a Vineyard Boulevard crosswalk. The traffic signal was in her favor, according to her lawsuit.

The city determined that the accident was avoidable.

The driver, who is still operating a refuse truck for the city, said he didn’t see Harris when he made a right turn onto Vineyard, according to the records.

Harris, through her attorney, would not comment.

The settlement is the city’s sixth and largest by far involving lawsuits stemming from garbage-truck accidents over the past five years. The other five payouts collectively totaled about $153,000, according to department data.

Houghton said he couldn’t comment on whether the driver in the Harris case was disciplined, citing an ongoing investigation. He likewise declined to say whether the driver in the Ando case was disciplined, citing a pending union grievance.

The refuse truck drivers are represented by the United Public Workers, which did not respond to requests for comment.

To drive a multiton refuse truck for the city, a driver must have a valid commercial driver’s license. A suspension or revocation of that license because of a serious traffic infraction would mean the worker could not drive a truck.

The city provides drivers with refresher training every two years. Despite such training, dozens of avoidable accidents typically happen each year.

In December, for instance, a driver, apparently distracted by a car to his left, lowered a trash bin with the truck’s right-side mechanical gripper and struck a woman standing nearby.

The records do not indicate whether the woman was injured. But the city investigation determined the accident was avoidable.