Alabama CDL Air Brakes case studies
Alabama CDL Air Brakes · Put your knowledge to work in context.
The Alabama CDL Air Brakes knowledge test is the written exam a commercial driver must pass to have the air brake restriction removed from a Class A or Class B commercial learner permit or license. It is for drivers who will operate vehicles equipped with air-actuated brakes - tractors and trailers, dump trucks, buses, and similar heavy equipment - and who therefore need to show they understand how those systems work before they are allowed to drive them. The Alabama CDL Air Brakes case studies are 5 cases and about 3,290 words.
1The Long Downgrade With a Slow Leak
You are driving a loaded 5-axle tractor-semitrailer (about 78,000 lb) down a 6% mountain grade posted with a 35 mph truck advisory. You began the descent at 35 mph in a gear that holds you near that speed with light brake application.
704 words, about 4 min2Pre-Trip on a Cold Morning
It is 28°F and you are doing a pre-trip on a tractor-semitrailer that sat outside overnight. The engine starts and the air pressure gauge climbs slowly.
677 words, about 3 min3Split System Failure: One Half Goes Dead
You are driving a straight truck with a dual air brake system. Mid-route, the gauge for the primary (rear) circuit drops sharply toward zero while the secondary (front) circuit holds pressure.
653 words, about 3 min4The Parking Brake That Won't Hold on a Hill
You are parked on a paved lot with a noticeable slope, facing downhill, in a tractor-semitrailer. You set the parking brake and release your foot from the service brake.
612 words, about 3 min5Ice, Air, and the Brake That Won't Release
It is 20°F and you have been driving a tractor-semitrailer for two hours in freezing conditions. You stop for fuel and set the parking brake.
644 words, about 3 min