The primary sponsors are Sen. Frank Lautenberg, D-N.J., and Rep. Jim McGovern, D-Mass.

In introducing the bill, they said the legislation would improve safety and prevent excessive strain on the nation's roads, tunnels and bridges.

"We have long advocated for truck safety measures such as improved hours of service rules and are traditionally opposed longer and heavier trucks because of safety concerns, especially in today's congested driving conditions," Blain Rethmeier, a spokesman for the American Insurance Association, said.

The bill is titled, "The Safe Highways and Infrastructure Preservation Act of 2009."

It would extend the current weight limit and freeze on triple-trailers to the entire 160,000-mile National Highway System, while still allowing certain exemptions, including for firefighting equipment.

The NHS includes both interstate highways and smaller national highways. Most truck size and weight restrictions (53-foot length maximum and 80,000-pound weight maximum) already apply to the 44,000-mile Interstate Highway System.

The bill would extend certain restrictions to the much bigger 160,000-mile National Highway System (NHS).

The two sponsors said the bill would also close loopholes that allow the operation of overweight trucks and would establish an enforcement program to ensure accountability.

"Bigger trucks–both those that are heavier and longer than standard trucks–present safety risks, including longer stopping distances, increased risks of rollover and of trailers swaying into adjacent lanes," they said in a statement. "Research shows that a 100,000-pound truck with unadjusted brakes travels 25 percent further after the driver steps on the brakes than an 80,000-pound truck," they said.