An alarming number of commercial truck drivers are ignoring weight limits on Maine’s roads, putting unnecessary strain on the state’s infrastructure and threatening public safety.

The Associated Press reported Monday that 16 percent of the tractor-trailers in the state run overweight. In some places, more than 60 percent of the truck traffic is ignoring the law.

Policing truck weight is time-consuming and difficult. The informal warning system used by professional drivers quickly spreads word of when a weigh station is open or where police are doing mobile inspections. That knowledge allows truckers hauling too much weight to avoid detection.

The state, however, has hidden sensors in roadways around the state that track vehicle weight. The tool can’t be used for enforcement, but it gives authorities an idea about the frequency of violations and the toll that they take.

The state’s Department of Transportation told the AP that a single overloaded truck a day can shave one or two years off the life of a road or bridge, which costs the state about $8.4 million a year.

Heavy trucks are also more difficult to control. They’re more prone to rollovers and take longer to stop.

The AP reported that in 2004, 10,000 trucks were weighed by the state’s mobile enforcement teams. In 2003, there were 1,901 violations found.

Fines for overweight trucks were sharply increased in 2002. The state has a 40-person state police unit that tries to monitor truck traffic. But the numbers don’t lie. Paying fines for running heavy apparently is considered part of the cost of doing business.

If enforcement and heavy fines aren’t working, the state needs other alternatives. As it stands, the cost of too-heavy trucks imposes a significant cost on the state’s roads and bridges, shortening their lives and requiring expensive repairs and replacement.