Despite national reports of drivers slowing down to the speed limit or below on federal highways as a way to squeeze a little more mileage out of their gas tank, some law enforcement officials in Maine say they have yet to see the trend come to the state.

Lt. Donald Pomelow, who serves in Franklin, Somerset and northern Kennebec counties, said he has not seen any empirical evidence to suggest drivers are going the speed limit, which is 65 mph, to save gas.

Though he indicated being familiar with the trend that people are easing up on the accelerator to save gas, Pomelow felt the trend is one that has not "quite reached the state of Maine yet."

"I have not received any notice that there's been any slowing down of vehicles," he said.

Not so across the U.S. In some news reports, state police offices in New England, the Midwest and the South have reported issuing fewer speeding citations this year. Some offices, particularly in North Dakota, are equating the decreasing number to drivers wanting to save gasoline.

Though Pomelow said he lacked hard numbers to prove a correlation, he was not surprised if people were slowing down for the sole reason to save gas in their tanks.

"I'm sure there are people out there being prudent," he said of commuters. "(State police are) doing the same thing. We're watching how we stop at lights and take off from lights, especially since last fall when (gas) prices started rising."

The Maine Judicial Branch's violations bureau was unable to immediately provide statistics on the number of speeding citations issued on federal highways this year.

Pomelow said from his own experience within his troop barrack, however, troopers are "doing the same amount of traffic work we did last year."

To the drivers' credits, slowing down is the right idea, one Maine expert said.

Justin Poland, an associate professor of mechanical engineering of 29 years at the University of Maine at Orono, said the idea of driving slowly to preserve the amount of gas one has in their tank is "generally true."

"It is true to say the faster a vehicle goes, the more energy is takes to operate, and would require more fuel," Poland, who teaches courses in thermodynamics and heat transfers in combustion engines, said.

But, Poland warned, drivers who opt to go below the speed limit on federal highways should not expect to save gallons.

"The savings from it are very small," he said.

What does prevent gas from being wasted at slower speeds is if the engine is performing at its optimal -- or most efficient -- speed. Vincent Caccese, a colleague of Poland's at the University of Maine's Orono campus, added when engines exceed their optimal speed, that's when drivers start seeing less gas in their tanks -- and start spending more to fill up.

"If (the engine) were to run at 80 miles per hour -- not that I would recommend doing that -- it won't run as efficiently as it would at 60 miles per hour," Caccese said.

While 60 mph is generally used in reports as the starting point before drivers can start calculating how much they would pay per gallon if they go any faster, both professors warned the optimal speed is different in many different makes and models and should not be considered a "universal threshold," Poland said.

Not only are some drivers slowing down, some are spending less time on the highways altogether.

Drivers in the U.S. drove 1.4 billion miles less in April than they did in April of last year, and 30 billion less this year than last year, Doug Hecox, a spokesman for the Federal Highway Administration, said.

"It's a pretty significant amount," Hecox said.

Still, Hecox added, to specifically say drivers are slowing down for the purpose of keeping more gas in their tanks is difficult.

"I cannot speak to the issue of people slowing down, but I can say they are certainly driving less," Hecox said. "I think, generally speaking, people have become more aware of conserving gasoline and are now driving sensibly."

Meghan V. Malloy -- 623-3811, Ext. 431

mmalloy@centralmaine.com