Engine Brake Policy

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Fond du Lac County Highway Department


Engine Brake Signing Policy


A.  Purpose

 Many large trucks are equipped with an engine braking system which utilizes engine exhaust to slow the vehicle.  This system of braking is commonly referred to as compression braking or a "Jake Brake". Sometimes, when truck engine brakes are applied, they produce a very loud and often undesirable exhaust noise.

 There are several advantages to having engine brake systems on large trucks.  In addition to assisting deceleration,  when a truck engine brake system is engaged, it helps prevent the conventional truck air brakes from overheating, thus saving on the normal wearing life of the truck air brakes.  This is especially true on roadways with steep downgrades with long distances where the safety of the truck can be enhanced by the use of the engine brakes.

 Several communities and Towns within Fond du Lac County have requested signing to prohibit this noisy braking method.  The Fond du Lac County Highway Department may permit Towns, Villages, or Cities request the placement of this signing on County Trunk highways under County jurisdiction subject to the requirements  of this policy.

 B.  Policy

 The following rules shall apply for Towns, Cities and Villages requesting truck engine braking signs on highways under Fond du Lac County jurisdiction:

1.  The local government must pass a local noise ordinance prior to requesting the signs.  The noise parameters listed in the Wisconsin Administrative Code- Chapter TRANS 405 may be used to help set noise level criteria.

 2.   The local government shall submit a written request to the Fond du Lac County Highway offices for a request for the County to install and maintain the signs. The cost of the signs as well as the costs for placement and maintenance will be the responsibility of the requesting agency.  The request for a sign installation from the local government should contain the following items:

 Copy of the local noise ordinance.

Proposed location of the sign or signs.

3.   It shall be the responsibility of the requesting agency to enforce the ordinance or the signs.

4.   The standard "NO ENGINE BRAKING EXCEPT IN EMERGENCY" sign (R10-64)  shall only be used on conventional highways at or near the corporate limits of the community or Town boundaries.

5.   The optional "WITHIN CITY or VILLAGE LIMITS:" sign (R10-64F) can be used to supplement the R10-64 sign if there are persistent or perceived problems with enforcement of engine braking on the roadway throughout the community.

6.  Due to potential concerns for the safety of truckers and other motorists, the signs shall not be used for steep downgrades that meet the following conditions:


5% grade and more than 3,000 feet long

 6% grade and more than 2,000 feet long

 7% grade and more than 1,000 feet long

 8% grade and more than 750 feet long

 9% grade and mort:: than 500 feet long

 Any grade steeper than 9% regardless of length


The location and use of these signs must be approved by the Fond du Lac  County Highway Department. In addition, all of the requests for engine braking signage will be reviewed and commented upon the Fond du Lac County Sheriffs Department.  The language of the signs used will meet the requirements of the WisDOT R10-64 and R10-64F sign plates as described in item 4.


Download Engine Braking Policy Here (.pdf)