Poorly maintained roads cost Hawai'i drivers an average of $503 a year as they shell out extra money for tire repairs and damaged shock absorbers.

That's one of the findings of a new report from U.S. Public Interest Research Group, which found that Hawai'i only trails New Jersey and California in terms of the highest costs paid annually by drivers as a result of rough roads and bridges.

"As the amount of road decay, potholes, bumps, clogged drainage systems and damaged bridges increases, so too do the number of accidents, the amount of money spent on car maintenance and the number of hours consumed by driving," said the report, "Road Work Ahead."

The report said there also is a cost in terms of the unsafe driving conditions that can lead to accidents, injuries and deaths. Poor road conditions were a contributing factor in about one-third of the nation's 34,000 highway fatalities last year, the report authors wrote.

"Without regular maintenance, roads turn into crumbled asphalt, erosion narrows shoulders and lanes, damaged drainage systems create hazardous floods, and broken retaining walls can allow boulders and other obstacles to obstruct a safe path," the report noted.

It also found Hawai'i had the seventh-highest percentage of roads in poor-to-mediocre condition, with more than one-quarter of streets and highways falling into this category.

The study also found costs are higher in metropolitan areas and that Hono- lulu ranked No. 5 among cities with populations of more than half a million. Costs due to rough roads was $688 annually.

The report said drivers in urban areas are likely to pay more because of the especially poor road conditions found in cities. Poor road conditions also contribute to traffic and delays as drivers slow to avoid potholes or lose control over rough patches.

U.S. PIRG said the nation needs a stronger commitment to repairs and should ignore special interests that push for new and bigger projects instead of maintenance.

"Federal and state policies ... often fail to achieve the proper balance between building new infrastructure and taking care of what we already have built," the report said.

"To counteract the tendencies to neglect repair and maintenance, we must adopt strong 'fix it first' rules that give priority to maintenance of our existing roads and bridges, set national goals for the condition of our transportation system and hold state governments accountable for achieving results."