What is one consequence of using a hand valve incorrectly while braking?

Using a hand valve incorrectly while braking can lead to more skidding than when using the brake pedal alone. The hand valve, which is typically used to control the trailer's brakes, can be engaged independently of the vehicle's primary braking system. If the hand valve is applied too quickly or too forcefully, it can result in the trailer's brakes locking up before the drive wheels of the tractor are properly engaged. This imbalance causes the trailer to skid, especially on slippery surfaces, as the wheels lose traction.

This incorrect application can lead to a dangerous driving situation, as it reduces overall control of the vehicle and can potentially cause it to jackknife. The key issue here is the disparity in braking force between the tractor and the trailer, which can increase the likelihood of skidding and losing control. This emphasizes the importance of using the hand valve with care and in coordination with the primary brakes to maintain stability and prevent skidding.