BAR HARBOR — Governors from six New England states and premiers from four eastern Canadian provinces agreed Tuesday that truck weight limits need to be harmonized if the two-nation region hopes to benefit substantially from transportation improvements.

In Maine, truck weights on Interstate 95 are limited to 100,000 pounds south of Augusta but north of the state capital the limit is 80,000 pounds.

In Canada, trucks can travel with two trailers on the federal highway system and can carry more than 137,500 pounds.

Leaders say this disparity complicates traffic patterns by forcing heavy trucks to take circuitous routes through northern New England as they travel from the Maritime Provinces either to southern New England or west to Quebec.

Maine Gov. John Baldacci and Vermont Gov. James Douglas each lamented the effect the truck weight limits have on the region, but not just on its economy.

Baldacci said that, though safety advocacy groups claim the limits make highway travel safer, they actually make it “more dangerous” on the secondary roads and in the small towns where the limits force the heavier trucks to go.

Douglas agreed that one truck weight limit for the entire region would be good for both the economy and for public safety.

“It’s been so frustrating for our state,” Douglas said. “It’s been environmentally detrimental to our state by forcing trucks to go through our small towns. We need to get some effort to get uniformity.”

The state and provincial leaders are meeting for a day-long conference at the Bar Harbor Club, located on West Street overlooking Frenchman Bay. It is the 32nd annual meeting for the executives, who are expected to wrap up the conference Tuesday afternoon.

Quebec Premier Jean Charest called for his colleagues at the conference to endorse a continent-wide adoption of California’s tailpipe standards, which call for a 30 percent reduction in tailpipe greenhouse gas emissions by 2016.

Last year, automobile manufacturers unsuccessfully sued the state of California, which voted in 2002 to adopt the standards, on the grounds that the state law were pre-empted by federal regulations and United States foreign policy.

Charest said Quebec supports a proposed cap-and-trade system, by which some polluters could acquire the rights to create more emissions than others as long as the total amount of emissions by all polluters did not pass a certain limit.

“In Quebec, we have taken the position that we support California standards,” Charest said. “[But] we’ve never said we will do it alone.”

The Quebec premier encouraged all the governors and premiers at the conference to endorse the same standards and to inform their respective federal governments of that support.

“As far as I know, we would be the first region to speak to that,” Charest said.

Energy and economic development are among the other topics that the premiers and governors are expected to discuss at Tuesday’s event.