The regulation, which takes effect next month, requires all minor damage to windshields outside of the wiper-sweep on both the driver and passenger sides to be repaired. Because there is no deductible on glass claims, most drivers currently replace a damaged windshield, even though the typical $400 replacement cost is seven to eight times greater than a repair.
The measure also requires that insurers ''shall use reasonable efforts'' to inspect damaged windshields before replacements are done to make sure they can't be repaired. That will be far less convenient for consumers, who currently can order windshield replacements without getting approval from their insurance company.
Insurance Commissioner Julianne Bowler approved the regulation in an effort to rein in the rising cost of glass claims, which have nearly tripled over the last decade to $151 million. In 2001, the most recent year for which figures are available, glass claims jumped 20 percent.
But Daniel Johnston, president of the Automobile Insurers Bureau of Massachusetts, said the regulation approved by Bowler is so watered down that it is unlikely to reduce glass costs significantly. He said the inspection requirement for windshield replacements could actually push costs up, forcing premiums higher.
The insurance companies and consumer representatives had pushed for a regulation that would have required drivers to repair any minor damage to their windshields outside of an 8 1/2-by-11-inch critical viewing area in front of the driver. Minor damage was defined as cracks shorter than 6 inches and stone breaks and bull's-eyes less than 1 inch in diameter.
Johnston said the proposal was expected to cut claim costs by $15 million, savings that were reflected in this year's rates.
But after a hearing on the issue in February, at which glass companies strongly objected to the proposed regulation, Bowler decided to widen the critical viewing area to include the area covered by the sweep of the windshield wipers on both sides.
Bowler's spokesman, Chris Goetcheus, said the commissioner merely adopted the language on critical viewing area used in the original glass proposal endorsed last year by the insurance bureau and Attorney General Thomas F. Reilly. Goetcheus said the bureau amended the proposal in January to narrow the definition of critical viewing area to the size of a standard sheet of paper.
''The commissioner opted to go with the original proposal,'' Goetcheus said, noting it matches the definition used by the Registry of Motor Vehicles. ''This obviously is going to help control costs, but to what extent it's too early to tell.''
Glass industry officials say 2 percent or less of damaged windshields are repaired in Massachusetts, compared to 15 to 20 percent nationally.
At the hearing in February, the Massachusetts Glass Dealers Association demonstrated the effect of the insurance industry proposal by covering every part of a windshield except for a standard paper-size section in front of the driver. ''It was ludicrous that that was the only area that would be considered critical,'' said James Torley, legal counsel to the association.
The regulation also mandates that vehicles damaged after Jan. 1, 2004, be repaired with original manufacturer parts if the vehicle has less than 20,000 miles. The current threshold is 15,000 miles.
The ruling was a partial victory for the state's auto body shops, which had been pushing for a much higher threshold. The body shops say the cheaper generic parts required for most cosmetic repairs don't fit properly and are unsafe. Johnston said the more expensive manufacturer parts will drive up insurance costs.