How Engine Brakes Work

Engine Brake Legislation

The United States Environmental Protection Agency (EPA) requires all trucks manufactured since 1988 to produce 80 db(A) of noise at 50 feet (15.2 meters). This range includes the exhaust system. The EPA also prohibits removing noise-reducing equipment from any vehicles [source: Jacobs Vehicle Systems].

Engine brakes are not always to be blamed for the loud noise that is so often heard on the road and can be bothersome to residents along heavy-use highways. Improper exhaust systems can be the problem, and many states are enacting legislations stating this:


  • In 2003, Montana required mufflers on all commercial vehicles equipped with engine brakes, per Bill 237. Any person who violates the bill is guilty of a misdemeanor and will be fined $500 [source: Montana Legislative Services].
  • The 2000 Colorado House Bill 00-1142 requires any vehicle equipped with an engine compression brake device to have a muffler. Violators are subject to a $500 fine [source: Jacobs Vehicle Systems].
  • In a multistate highway transportation agreement, Arizona, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming adopted legislation based on the Colorado law that requires mufflers on any vehicle equipped with an engine brake. Any persons violating the legislation will be required to pay a $500 fine [source: Jacobs Vehicle Systems].

If you are bothered by engine brake noise, contact your local authorities and request that legislation be enacted in your state, too.