Seventy percent of the 386 traffic accidents involving municipal garbage trucks over the past five years were avoidable, according to the city’s own reports, yet city officials are unable or unwilling to say how many errant drivers are disciplined each year.

This glaring lack of public accountability in Oahu’s taxpayer-funded Department of Environ- mental Services must be swiftly corrected. Careful management of errant drivers literally is a matter of life and limb.

Star-Advertiser reporter Rob Perez analyzed five years worth of accident summaries, obtained from the city through a public records request, and found that the city’s own investigations concluded that 271 accidents from 2009 to 2013, or 70 percent of all incidents, were avoidable — meaning that the garbage-truck drivers involved did not take reasonable precautions to prevent the collisions.

Most of the incidents were minor, typically involving the trucks dinging a mailbox or nicking a tree. But sometimes the huge trash trucks hit parked cars, causing expensive damage. And in the worst cases, the drivers failed to notice people, killing or injuring motorists or pedestrians. Among recent victims: an 83-year-old pedestrian who was killed last year by a garbage truck backing out of a cul-de-sac and a 68-year-old woman whose foot had to be amputated in 2012 after she was struck while in a marked crosswalk.

These severe cases are tragic for the victims, of course, and costly for the taxpayers. The city has agreed to pay a total of at least $1.4 million over the past five years to settle six lawsuits.

The avoidable-accident rate peaked at 74 percent in 2011 and 2012 and dropped to 64 percent last year, according to the newspaper’s data analysis. That it was left to the Star-Advertiser to analyze these traffic summaries is part of the problem: The city investigates each individual accident, but does not track the data on an annual basis, depriving managers of an important monitoring tool that could help lower the rate of avoidable mishaps. Greater awareness of the overall problem is an important step toward a broad solution.

Even worse, the environmental services department does not maintain statistics on the number of drivers who are disciplined each year for inattentive driving that results in an accident, whether anyone is injured or not. It’s true that personnel rules and labor contracts regarding Oahu’s unionized city trash collectors prevent the city from disclosing details of ongoing investigations or pending grievances and require records of specific disciplinary actions to be purged after two years. However, those rules shouldn’t preclude the department from tracking the overall number of disciplinary cases from year to year. Such aggregate data could help determine whether training programs and other measures are effectively lowering the number and type of mishaps, which are defined as avoidable, unavoidable or as providing insufficient evidence to make a finding.

The city’s garbage truck drivers are represented by the United Public Workers. As is so often the case when it comes to disciplinary matters regarding government employees in Hawaii, whether the union is UPW or another labor organization, rules intended to protect individual privacy serve to shield entire departments, including management, from public scrutiny.

Scarce accountability for the city’s trash fleet is but one example of this phenomenon. Given the grave risks to bystanders when a garbage-truck driver makes a mistake, the city should doggedly track these mishaps and, over the long term, change disciplinary rules that favor privacy for individual government employees over transparency for the taxpayers.