What Is an Engine Brake Ordinance? Key Facts & Regulations

An engine brake ordinance is a law that regulates or prohibits the use of engine braking systems, primarily in large diesel-powered vehicles like semi-trucks and buses. The goal of these ordinances is to reduce or eliminate the loud noise associated with engine braking in order to maintain community peace and quiet.

What Is Engine Braking?

Engine braking, also known as compression braking or jake braking, is a technique used to slow down and control the speed of large vehicles without relying solely on the wheel brakes. Here’s how it works:

  • The engine pistons compress air during the combustion stroke. This builds up a high pressure inside the cylinder.
  • When the exhaust valve opens, this high-pressure air escapes the cylinder. The rapid release of compressed air makes the loud distinctive braking noise.
  • The engine has to work hard to compress the air again for the next combustion stroke. This absorbs energy and slows the vehicle down.

Engine braking provides several benefits:

  • It assists the wheel brakes and reduces overheating and wear. Brakes can overheat and fade when used extensively on steep grades.
  • It allows descending steep hills at a controlled speed. The compression braking helps maintain a steady speed.
  • It gives the driver more control in slippery conditions when wheel braking alone may cause the wheels to lock up.

However, it comes with one major downside: noise pollution. The loud noises from engine braking can produce up to 110 decibels, disrupting neighborhoods and businesses. This led to the implementation of laws prohibiting or restricting the practice.

Why Were Engine Brake Ordinances Created?

Excessive engine brake noise has long been a nuisance for communities near highways, residential streets, or other areas with significant truck traffic. The primary motivations behind engine brake ordinances are:

  • Noise control – Reducing disruptive and excessive noise to maintain a peaceful community. Engine braking noise can be comparable to a loud stereo system, disrupting sleep, conversations, etc.
  • Quality of life – Creating a more livable community by minimizing noise pollution. This makes neighborhoods more desirable and protects property values.
  • Safety – Engine braking noise can mask emergency vehicle sirens or other important sounds, creating danger. It can also cause hearing damage with prolonged exposure.
  • Complaints from residents – Councils and lawmakers responding to citizens’ appeals for relief from noise.

Engine brake ordinances provide police and law enforcement a means to address noise complaints related to engine braking. Fines, penalties, and bans give them the legal backing to enforce noise reduction.

Where Are Engine Brake Ordinances Implemented?

Engine braking noise affects certain areas more than others. As a result, ordinances are usually implemented in:

  • Residential neighborhoods – protecting citizens from excessive noise at home.
  • Business districts – reducing disruption to offices, shops, restaurants, etc.
  • Hospitals and nursing homes – safeguarding patient rest and recovery.
  • Schools – limiting noise that could impact learning.
  • Areas with high traffic volume – controlling noise from large truck activity.
  • Hillside communities – mitigating noise that echoes off hillsides and amplifies the problem.
  • Historic downtowns – preserving the charm and ambience of these areas.
  • Nighttime hours – prohibiting engine braking noise that disturbs sleep.

Posting signs is a common way to designate zones where engine brake use is prohibited. This gives truckers advanced warning so they can turn off braking systems if possible.

What Do Engine Brake Ordinances Prohibit?

Though the specific provisions vary between jurisdictions, engine brake ordinances typically prohibit:

  • Using engine compression brakes to slow or control vehicle speed, except in emergencies.
  • Allowing engine braking noise that exceeds certain decibel limits, usually 80-83 dB.
  • Operating loaded tractor-trailers that produce excessive noise from engine braking.
  • Using engine retarder brakes or engine braking during nighttime hours, usually between 10 pm and 6 am.

The ordinances allow engine braking only when necessary for safety, and not as a routine braking method. Drivers may still use compression brakes to avert danger, even in prohibited areas.

Exceptions to Engine Brake Ordinances

While engine braking is largely banned under these noise laws, certain exceptions permit its use when absolutely necessary:

  • Emergencies – Engine braking can be activated to avoid accidents or hazards where wheel braking alone would be inadequate. This accounts for safety needs.
  • Testing – Ordinances allow businesses like truck repair shops to test engine braking systems. This is limited to daytime hours and conducted away from homes.
  • Transit buses – Some ordinances exempt public buses from bans, permitting their safe operation.
  • Steep grades – Select laws allow engine braking on prolonged steep declines where overheated wheel brakes could fail.

These exceptions acknowledge that compression braking remains vital in certain circumstances for large vehicle control and safety. Complete bans could compromise safe operation.

How Are Engine Brake Ordinances Enforced?

Enforcing engine braking ordinances comes with challenges since violations are not always easily observed. Common enforcement methods include:

  • Traffic patrols – Officers monitor prohibited zones and listen for braking noise violations. They can then pull over offenders.
  • Weigh stations – Trucks may be screened for modified or disabled braking silencers meant to circumvent the law.
  • Noise meters – Sound level meters measure decibel levels consistent with illegal compression braking. This documents violations.
  • Citizen reporting – Residents will call police to report noisy braking activity for investigation.
  • Surveillance cameras – Cameras capture braking violations, allowing citations to be mailed to the vehicle’s registered owner.

Penalties for violating engine brake ordinances include fines ranging from $100 to $500 in most areas. Repeat violations often face increased fines and penalties.

Why Do Some Truckers Violate Engine Brake Ordinances?

Given the penalties, why would truck drivers contravene engine braking laws? Several factors motivate non-compliance:

  • Habit or forgetfulness – Drivers accustomed to engine braking may do it instinctively.
  • Disagreement with ordinance – Some may intentionally disregard a law they deem unreasonable.
  • Necessity on long declines – Braking may be deemed necessary for safety on steep sustained grades.
  • Lack of warning signs – Missing or obscured signs provide an excuse of ignorance.
  • Difficulty turning off system – Older trucks require mechanics to disable the braking system.
  • Minimal enforcement – Lack of traffic patrols reduces the perceived risk of getting caught.

Ultimately, even minor non-compliance impacts community liveability. Consistent and fair enforcement is key to gaining high compliance rates over the long term.

Arguments For and Against Engine Brake Ordinances

Engine braking laws remain controversial among commercial drivers and are not universally embraced. Common arguments include:


  • Protect community quiet and quality of life.
  • Reduce disruption to homes, businesses, and pedestrians.
  • Improve walkability, ambience, and charm of neighborhoods.
  • Ensure restful sleep by banning nighttime engine braking.


  • Infringe on commercial freedoms and rights.
  • Make trucking operations and deliveries more difficult.
  • Take away an essential safety mechanism for stopping large trucks.
  • Burden truckers who may be unaware of localized ordinances.

Complex factors are at play, requiring a compromise between community interests and practical transportation needs.

New Quieter Braking Systems

In response to noise complaints, truck and brake manufacturers are engineering new systems to enable quieter braking:

  • Encapsulated exhaust mufflers reduce braking roar without affecting performance.
  • Noise-canceling technology uses destructive sound interference to cancel noise.
  • Torsional shock absorbers minimize mechanical noises during braking.
  • Electronically-controlled systems apply the brakes more gradually to avoid sudden loud release of compressed air.
  • Plasma ignition chambers greatly reduce the combustion noise.
  • Exhaust diffusers direct the noise upwards away from populated areas.

As these technologies improve and become more widespread, engine braking noise could be mitigated without needing to ban the practice outright. This could strike a balance between community and industry needs.

The Future of Engine Brake Ordinances

Engine braking noise remains an ongoing quality of life issue, especially with truck traffic projected to increase over the coming decades. Several possible paths lie ahead for ordinances:

  • Expanded prohibitions – More local and state governments adopt ordinances banning excessive braking noise.
  • Targeted laws – Laws aim to reduce noise primarily in residential and pedestrian zones.
  • Broader adoption of mufflers – Mandates require noise-reducing equipment on new trucks.
  • Shift to bans on decibel levels – Laws forbid noise over certain sound thresholds without banning techniques.
  • Industry compromises – Truck makers voluntarily implement quieter braking to stave off proliferating bans.
  • Growth of electric trucks – Electric motor braking generates little noise, reducing community impact.

Citizen demands for quiet and trucking industry considerations will continue shaping policy on engine braking noise control. Ongoing dialog and creative solutions will be needed to find an optimal balance.

While engine braking remains an indispensable tool for truck safety, engine brake ordinances seek to curtail its disruptive noise impact on neighborhoods and business districts. As braking technology evolves, the laws will likely adapt to protect community interests without jeopardizing operational efficiency and road safety. Careful compromises can create a quieter, more sustainable transportation system.

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