Wyoming CDL Permit Test - Double

Shut-off valves are used in air supply lines to control the passage of air from one trailer to another. The rear shut-off valve should always be closed to prevent air from leaving the braking system.

To reduce the risk of tipping over when driving with a trailer, you should steer gently and smoothly. Avoid making sudden movements.

More than half of all accident-related truck driver deaths are a result of truck rollovers. To help prevent a rollover, be sure to load cargo low to the ground and centered on your rig. Take corners slowly and carefully.

Height warnings are often, but not always, posted on low bridges. If you are unsure if you will be able to clear an overhead object, go slowly.

If you are being followed too closely, you should increase your following distance, avoid making quick moves, and avoid relying on tricks (such as flashing your lights) to help other drivers pass. Speeding up may only increase the danger by causing the tailgater to continue tailgating you at a higher speed.

Because you can't see everything behind you, backing is always dangerous and should be avoided whenever possible. Choose parking spaces from which you can pull forward when you leave.

Never unlock the pintle hook with the dolly still under the rear trailer. This could cause the dolly tow bar to fly up, possibly causing serious injury.