For safety purposes, when is it best to turn off a retarder?

Turning off a retarder during slippery roadway conditions is crucial for safety because a retarder enhances braking by creating resistance in the drivetrain, which can sometimes lead to a loss of traction. Slippery surfaces, such as those caused by ice, snow, or rain, can significantly reduce a vehicle's grip on the road. When a retarder is active in such conditions, it can contribute to wheel lock-up or sliding, making it difficult to maintain control of the vehicle.

Conversely, on a flat road, the retarder can be beneficial for maintaining a steady speed without consistently applying the brakes. In heavy traffic, the retarder may help in regulating speed and providing safer braking distances, while in high wind conditions, deactivating the retarder may not be necessary if the road surface is stable and traction is not compromised. The key factor in this instance is the potential for slippery conditions to adversely affect vehicle control, making it vital to turn off the retarder to ensure safe driving.