AUGUSTA, Maine — A legislative committee Tuesday unanimously backed a bill that would let the state’s transportation commissioner raise the speed limit to 75 mph on Maine’s interstate highways.

The measure next heads to the full Legislature.

The Legislature’s Transportation Committee agreed to the legislation, LD 654, after lawmakers on the panel sought assurances that the bill’s passage wouldn’t automatically lead to increased speed limits throughout the state, especially in congested areas.

Nina Fisher, the Department of Transportation’s legislative liaison, said the transportation commissioner would change the speed limit on a section of highway only after the department conducts a thorough engineering analysis and secures approval from the chief of the Maine State Police.

“I can say with 100 percent certainty the commissioner is not going raise the speed limit to 75 through Portland,” Fisher told committee members.

The bill would not apply to the Maine Turnpike, where the transportation commissioner doesn’t have the authority to set speed limits.

During debate on the bill, lawmakers raised concerns that increased speeds diminish fuel economy and that high-speed crashes are more dangerous than accidents that happen at lower speeds.

“I’m a little suspect of human nature. I think if you set it at 75, they’re going to go 85. If you set it at 85, they’re going to go 95,” said Rep. Wayne Werts, D-Auburn. “I’m not sure I want the aging population going 75 mph down the highway.”

As originally written, the speed limit bill would grant the state transportation commissioner authority to raise the speed limit to 75 mph only on Interstate 295, which runs from Scarborough to West Gardiner. The bill’s sponsor, Rep. Justin Chenette, D-Saco, suggested amending his bill to allow the transportation commissioner authority to raise the speed limit to 75 mph on all interstate highways in Maine.

At a public hearing earlier this month, Chenette cited U.S. Department of Transportation research that showed speed limit changes have little effect on drivers’ travel speeds. In addition, the same research showed the number of accidents decreased in experimental areas where researchers raised the speed limit and increased in areas where the speed limit was lowered.

A representative from AAA Northern New England raised concerns about safety hazards from raising the speed limit.

LD 654 comes about two years after the Legislature allowed the transportation commissioner to raise the speed limit on I-95 between Old Town and Houlton to 75 mph. That speed limit change took effect in the fall of 2011.

Rep. Beth Turner, R-Burlington, said she hasn’t noticed a change in driving speeds on that stretch of highway since the speed limit increased.