Another study has found that allowing heavy trucks on the interstate, rather than the back roads, saves money and lives. The latest study, mandated by the federal government, found that allowing trucks weighing more than 80,000 pounds on the Maine and New Hampshire turnpikes saved up to $4 million and dramatically reduced accidents.

Despite support from Maine’s congressional delegation and the governor, Maine’s proposal to increase the weight limit to 100,000 pounds on its interstate highways continues to face stiff opposition from safety advocates who argue that large trucks are too dangerous. Recent studies, including this one, however, show that putting trucks on divided highways with four or more lanes is much safer than forcing them on to rural roads, many of which wend through cities and town.

Trucks exceeding 80,000 pounds are barred from the interstate north of Augusta. An exemption granted in 1998 allows trucks weighing up to 100,000 pounds to travel on the Maine Turnpike and truck carrying jet fuel are allowed to use the highway to get to Bangor International Airport to supply military planes. The current study, a draft of which was released last week, was required by the Federal Highway Administration as a condition of the 1998 exemption for the Maine Turnpike.

The study, conducted by Wilbur Smith Associates, an international infrastructure consulting firm with an office in Portland, found that the accident rate, per hundred million vehicle miles traveled, was more than four times higher on two-lane roads than on the Maine Turnpike between 2000 and 2003.

The fatal crash rate on “diversion routes,” the largely two-lane undivided highways heavy trucks are now forced to travel, was 10 times higher than the Maine Turnpike and interstate routes, based on miles traveled. Accidents involving serious injuries were also less frequent on the turnpike and interstate than on diversion routes.

Thus, the study concluded that if Congress were to remove the current weight exemption on the Maine Turnpike – in other words, to again bar trucks over 80,000 pounds from that highway – the net impact for Maine would be more crashes annually.

If the safety arguments for raising the weight limit is not sufficiently persuasive, the consultants also found that costs to maintain roads could be lowered. If the turnpike exemption were to end, the state would spend up to $2.4 million more annually on pavement rehabilitation and an addition $800,000 a year on bridge maintenance.

The ramifications of the 80,000-pound limit were highlighted in recent debates over the expansion of the West Old Town Landfill. Many local residents objected to an increase in trucks hauling garbage through their towns and neighborhoods. Most of the trucks headed to the landfill, which is less than a quarter of a mile from an interstate exit, would not be able to use Interstate 95 to get there.

For reasons of economics, safety and common sense, the weight limit on Maine’s interstate should be raised.