AUGUSTA — The speed limit is increasing by 5 mph on nearly all of Interstate 295, as well as most of Interstate 95 north of Augusta to Old Town, state officials announced at a press conference Tuesday morning.

The changes took effect Tuesday, and new signs are being posted along the changed sections of the interstate.

The Maine Department of Transportation increased the speed limit from 65 mph to 70 mph on I-295 north of Tukey’s Bridge in Portland to mile marker 51 in Gardiner, which is most of the highway.

The department also increased the speed limit by 5 mph on I-95 from mile marker 114 in Augusta to mile 126 in Waterville, and from mile 134 in Fairfield to 181 in Bangor, in both cases from 65 mph to 70 mph. North of Bangor to Old Town it goes from 65 to 70. North of Old Town the speed limit is 75 to the end of the highway in Houlton.

Speed limits were also increased on small sections of highways connected to or near I-295 and on Interstate 395 from I-95 to U.S. Route 1A in Bangor and Brewer.

Department of Transportation Commissioner David Bernhardt said at the press conference Tuesday that the new speed limit signs were being posted and should all be up within a day.

The department already increased the speed limit from 65 mph to 75 mph on the northern part of I-95 between Old Town and Houlton in 2011 after the Legislature passed a law allowing the increase. A law passed last year gave Maine Department of Transportation the power change interstate speed limits with approval from Maine State Police.

The increase better matches the speeds at which people are actually driving, Bernhardt said. Radar data showed that most vehicles travel faster than 70 mph on the interstate for a majority of the day, according to the department.

“The most important reason is it’s much safer on any road if the operating speed and the posted speed are close together,” Bernhardt said.

He doesn’t expect people to start driving faster as a result of the higher speed limit. When the speed was increased by 10 mph on the north portion of I-95 in 2011, the average speed only increased by 1 mph, he said.

“People are driving at their comfort levels. People aren’t going to be driving faster than that,” Bernhardt said.

Maine State Police Chief Col. Robert Williams said at the press conference that the higher speed limit means drivers must be leave a greater distance between themselves and the vehicles in front of them. He also said it’s even more important for people driving in poor weather to drive slower.

The interstate speed limit in most of Maine has been 65 mph since 1987. That limit that was set arbitrarily, Bernhardt said, after Congress lowered the national speed limit to 55 mph in 1973 as a way to conserve energy in response to the 1973 oil crisis. The national speed limit law was repealed in 1995, returning authority to states.

The Maine Turnpike Authority plans to increase the speed limit to 70 mph from 65 mph on the Maine Turnpike from Kittery to Scarborough and from Westbrook to West Gardiner, but the change won’t take effect until midsummer.

Paul Koenig — 621-5663 | [email protected] | Twitter: @paul_koenig