Nebraska CDL Permit Test - Knowledge Test Class A

A modulating control valve allows a driver to gradually apply spring brakes. In equipped vehicles, the valve is controlled by a lever located on the dashboard.

Eating while driving can be a dangerous distraction to the driver both because it diverts their attention away from the task at hand and requires them to remove a hand from the steering wheel.

Front-end header boards protect the driver from the forward motion of their cargo in the event of a crash or emergency stop.

The majority of heavy-duty vehicles are equipped with dual air brake systems.

On a steep downgrade, you must use the engine's braking effect as your primary method of speed control. Be sure to decelerate and downshift appropriately before beginning to drive down the hill.

Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when air tank pressure falls to a level between 20 and 45 psi. You can do this by chocking the wheels and releasing air from the braking system by stepping on and off the brake pedal. Once the pressure levels drop to an unsafe level, the parking brake valve should pop out and spring brakes should come on.

You can tell that your vehicle is equipped with an Anti-Lock Braking System (ABS) if it has a yellow ABS malfunction lamp on the instrument panel.