What factor may necessitate turning off the retarder?

Turning off the retarder is especially important in icy or snowy conditions. A retarder is designed to provide effective braking by using engine braking or exhaust braking, helping to slow down a vehicle without using the traditional brakes. However, when road conditions are slippery due to ice or snow, relying on a retarder can cause the wheels to lose traction. This can lead to skidding or loss of control, making it crucial to use traditional brakes more cautiously in such conditions. In contrast, hot weather, heavy traffic, or flat road surfaces do not carry the same risks of losing traction as icy or snowy conditions do. Therefore, understanding when to turn off the retarder is key to maintaining safety on the road, especially in adverse weather.