Which of the following statements about the use of retarders is true?

Using retarders can indeed cause skidding on surfaces with poor traction. Retarders help to slow down a vehicle by providing additional braking force, especially in heavy trucks. However, when road conditions are slick due to rain, ice, or snow, the use of retarders can make the wheels slip or skid because they can significantly increase the vehicle's deceleration. This risk highlights the importance of adapting driving techniques and braking mechanisms to current road conditions to maintain safe control of the vehicle.

In contrast, the other statements do not accurately represent the function or guidelines surrounding the use of retarders. For example, while they should be used cautiously, they are not limited to just dry conditions. Retarders are still very relevant and beneficial in modern vehicles, particularly when used responsibly. Additionally, retarders are designed primarily to help maintain speed on descents rather than improve acceleration rates.