Braking signs target excess noise

Dec 31, 2023

Debbie Smith

Bangor

A: Ever hear a tractor-trailer making a load of noise, sounding as though the driver is down-shifting into lower gears to help slow down, and in doing so making a racket from the exhaust, ”whomp, whomp, whomp, whomp, wah wah wah wah ? ”?

That sleep-disturbing sound is attributed to brake retarder systems installed on many of the big rigs, Debbie, and the signs often are posted by municipal officials in response to neighborhood complaints about the noise.

”Residents will complain about the noise from the Jake Brakes,” said state Department of Transportation local spokesman Ron Young, noting that the municipalities must have the state’s permission to install the signs.

The trucking industry and brake-retarder manufacturers dispute the assertion that the brake-assist systems are responsible for the racket.

Marian Zincke, marketing director for Jacobs Vehicle Systems, manufacturer of the original engine-braking device known as the ”Jake Brake,” said his company’s product produces a small amount of noise in excess of that created by the truck engines, but that it’s well within federal standards and is not responsible for the booming rat-tat-tat-tat-tat sound that annoys some folks.

The Jake Brake uses changes in valve timing to restrict the flow of exhaust gases, resulting in back pressure that creates resistance during the exhaust stroke, thus slowing the engine, and the truck along with it, Zincke explained.

In that respect, it works in a manner similar to down-shifting, which also creates engine resistance to help slow vehicles. But down-shifting does not work as well to reduce speed in big rigs as it does with cars, Zincke said, because diesel engines don’t offer as much resistance, and because the weight of a loaded tractor-trailer overwhelms the braking effect of the engine.

Jake Brakes and other engine-braking systems ? there also are hydraulic and electromagnetic designs ? are supposed to supplement the regular mechanical brakes, so drivers should be using both systems, said Dan Smyser, chief of PennDOT’s maintenance division in Harrisburg. The systems can be switched on or off by the driver.

”They should use the brake and the retarder,” he said, insisting that the retarders do not make excessive noise when properly used and functioning properly.

”If those things are in proper working order, you don’t even know they’re working,” at least not because of noise, said Don Siekerman, safety director for the Pennsylvania Motor Trucking Association.

The problems really are caused by ”a small minority of truckers out there who want to hear their trucks make noise,” and who modify their mufflers to that end, Siekerman said.

The retarders help prevent overheating of the mechanical brakes, and can be considered safety devices. They can help prevent brake fade, which can be responsible for runaway trucks. That’s why the prohibition zones are not allowed on steep grades or on roads where rear-end crashes are prevalent, Young said.

”It is a safety issue,” said Siekerman, noting that, in Pennsylvania, trucks hauling oversize loads are required to have engine-braking devices.

The prohibition zone on Route 512 in Moore Township is relatively new, as you suspected, Debbie. It was implemented in June.

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