Kentucky CDL Permit Test - Double

Hydroplaning is an effect in which a vehicle's tires lose traction with the surface of the road and instead glide along a layer of water. There does not have to be a large amount of water on the road for this to occur.

An Anti-Lock Braking System (ABS) intervenes to reduce brake pressure if there is a risk of wheel lockup. If the ABS isn't working, the vehicle's basic braking functions are not affected. A driver should continue to drive and brake in a normal manner.

When operating a double or triple, the shut-off valves at the rear of last trailer should be closed. All other shut-off valves should be open.

Gravity causes a vehicle's speed to increase when traveling on a downgrade. Adjust your speed before reaching a downgrade.

When stopping, press down the brake pedal smoothly and gradually.

Black ice is a layer of ice that is thin and clear enough for the road to be visible through it. The surface will look like a wet road. Always be alert to black ice if the road looks wet when the temperature is below freezing.

When inspecting the engine compartment, you should check the oil level, coolant level, and windshield washer fluid level, among other things.