HAMPDEN – Moving from a larger city to Hampden three years ago, Nancy and Charlie Hamilton chose a house fairly close to the main road so they wouldn’t miss the feel and sounds of city life.

But the couple has had more of an earful than they wanted.

Truckers driving with increasing frequency past the Hamiltons’ home are making their presence known with a loud rumble as they use engine brakes to slow their massive vehicles.

“I wanted to hear the sounds of people; I just didn’t want to hear those brakes,” said Nancy Hamilton, who is frustrated at what she calls unnecessary brake noise.

With the speed limit set at 30 mph and her home about one-eighth of a mile from the traffic lights on U.S. Route 1A, Hamilton, the daughter of a truck driver, wonders why it is necessary to use the brakes.

She suspects excessive speed is the reason.

“They zoom right down through here,” Hamilton said.

Questions and concerns such as Hamilton’s prompted the Hampden Town Council on Aug. 18 to ban the use of engine brakes, commonly known by the trademarked name “Jake Brake,” one of several brands of engine-retarding devices. Communities around the state and even across the country have addressed the issue, with varying results.

Places such as Camden, Bucksport and Ashland have chosen voluntary abstinence through posted signs asking truck drivers not to use the engine brakes. Brewer has a strict prohibition on use of engine brakes inside the city limits and is enforcing it.

Brewer Police Chief Steve Barker said recently that about a dozen truck drivers in a two-week period had been summoned for violating the engine brake ordinance. The city has had its engine brake ordinance in place for eight months. It initially covered only the nighttime hours but has been amended since to include all hours.

Anti-engine brake ordinances are a relatively simple answer to a growing concern. Unlike a noise ordinance that would require municipal officials to use specialized equipment to measure decibel levels to determine whether a violation occurred, an engine brake ordinance gives local police officers the latitude to determine, based on observations, whether the truck driver violated the ordinance.

But some trucking businesses in the area, including in Hampden, as well as the manufacturer of the Jake Brake, say the issue isn’t that simple and that such measures miss the point.

The real culprit, they say, is often the muffler, or lack of one.

Brian Mauriello, business development manager for Connecticut-based Jacobs Vehicle Systems – whose brake systems account for about 75 percent of those installed in heavy-duty trucks in North America – said that noise levels of properly equipped heavy diesel trucks that include engine brakes meet federal standards.

Noise levels substantially increase if the truck drivers modify, remove or have improper mufflers, he said.

The result: A federally accepted noise level could turn to glass-shattering levels. To get an idea about the difference in noise levels a truck muffler makes, Mauriello said, take the loud sounds a car makes without a muffler and multiply that by eight.

Feeling that the Jake Brake is being unduly blamed for the noise, Mauriello said a clear solution would be to enforce laws already in place in Maine that require mufflers on vehicles, whether commuter car or commercial carrier.

“Renegades” is how truck drivers refer to those who don’t have the necessary exhaust systems. For some it’s a matter of economics and saving money since mufflers can lower fuel efficiency, while for others it’s just the kick they get from the loud noise they make.

But the fact remains engine brakes also make noise.

Developed by a truck driver who narrowly missed hitting the caboose of a train after coming down a steep hill, devices that curb an engine’s power can mean quicker stops as well as reducing the chances of the wheel brakes overheating and becoming less effective.

Mauriello said the engine braking systems, which sell for about $2,200, can extend regular brake replacement from 100,000 miles to 500,000 miles.

For H.O. Bouchard, with its 75 trucks, engine brakes have meant significantly fewer brake replacements and saved hundreds of thousands of dollars per year, according to Steve Whitcomb. He has worked for H.O. Bouchard for more than 26 years and is now the Hampden trucking company’s safety manager.

Engine brakes work fairly simply. A flip of the switch turns them on and, once activated, they turn the diesel engine into an air compressor, soaking up hundreds of horsepower – up to 600 – and slowing the momentum of the truck, Whitcomb said. Inside the engine, exhaust valves open up, releasing the compressed air into the exhaust system.

Loaded with about 70,000 pounds of No. 6 fuel oil, a Bouchard truck rolled down Coldbrook Road in Hampden recently and onto U.S. Route 202, with Whitcomb behind the wheel. Approaching a small down grade, Whitcomb flipped the switch and almost immediately a guttural sound pumped out of the exhaust.

Without applying the foot brake, the fully loaded truck immediately began to slow, knocking 4 mph off the original speed of 55 mph, a small demonstration of the power-sapping ability of the engine brake.

From inside the cab, the noise didn’t sound much louder than the sound the truck engine makes as it accelerates from a stop, raising another point made by Mauriello. Eliminating the use of engine brakes doesn’t address the engine noise the trucks make going up a hill.

Further complicating the issue, said Mauriello, is that the engine brake is not just for slowing on a slope. The engine brake is on all the time when the truck is on cruise control, for example, waiting to kick in when needed, whether the truck is going 55 mph or 30 mph.

Caught in the middle, trucking institutions such as Pottle’s Transportation, Dysart’s Transportation and Bouchard said they would comply with the ordinances wherever they encounter them, although they lament the loss of additional safety and efficiencies the engine brakes provide.