CDL Vehicle Combination Practice Test

Negotiating a curve while driving a combination vehicle requires careful consideration of speed and control. Slowing down before entering the curve and maintaining a steady speed through it is crucial for several reasons.

First, combination vehicles are often longer and heavier than standard vehicles, which makes them more susceptible to the effects of momentum and centrifugal force. By reducing speed before entering the curve, you help ensure that the vehicle can navigate the turn without tipping, rolling, or losing traction.

Maintaining a steady speed through the curve allows for better vehicle stability. Sudden changes in speed or direction can lead to a loss of control, especially since the weight of the trailer can influence how the entire combination vehicle behaves in a turn. Entering the curve at a controlled speed helps manage the dynamics of both the tractor and the trailer, allowing them to follow a predictable path through the curve.

In contrast, accelerating through the curve can lead to an increased risk of skidding or losing control. Entering a curve at a constant speed without slowing down does not account for the added dynamics of a combination vehicle. Using the brakes in the middle of the curve can destabilize the vehicle, as it may cause the trailer to push against the tractor, increasing the chances of a jackknife situation.