OK CDL Air Brakes case studies
OK CDL Air Brakes · Put your knowledge to work in context.
The Oklahoma CDL Air Brakes knowledge test is the written exam a driver must pass to operate a commercial vehicle equipped with air brakes. It applies to Class A and Class B applicants whose vehicles use air brakes, and to drivers who already hold a CDL but carry an air brake restriction (typically restriction L) and want it removed. The test is administered on computer at Oklahoma Department of Public Safety testing locations. Content follows the air brake section of the CDL manual: system components such as the compressor, governor, reservoirs, and slack adjusters; the dual-circuit system and its safety valves; the pre-trip air brake inspection and in-cab tests; warning signals and pressure loss; normal stopping, downgrade control, and brake fade; emergency braking; and Oklahoma and federal rules on restrictions and endorsements. The OK CDL Air Brakes case studies are 5 cases and about 2,644 words.
1Dual-Circuit Pressure Loss Before a Downgrade
Malik is driving a 2021 three-axle tractor pulling a loaded van trailer on a two-lane Oklahoma state highway. The combination has a dual-circuit air system.
577 words, about 3 min2Failed Static Leak Test on a Loaded Combination
Renata is doing a pre-trip inspection on a 2018 tandem-axle tractor with a 53-foot dry van, a combination vehicle with air brakes. The engine is off, the system is fully charged to 120 psi, and the parking brakes are released.
544 words, about 3 min3Brake Fade on a Six-Percent Grade
Devon is driving a 5-axle tractor-semitrailer loaded to 76,000 pounds on I-40 in eastern Oklahoma. He approaches a sign reading '6% downgrade, 4 miles.' His speed at the top is 55 mph, and the posted truck speed is 45 mph.
553 words, about 3 min4Total Air Loss at a City Intersection
At 35 mph on a four-lane city street in Tulsa, Casey is driving a 26,000-lb straight truck with air brakes. The truck has a dual-circuit system.
509 words, about 3 min5Air Brake Restriction and an Intrastate Job Offer
Amira holds an Oklahoma Class A CDL with an 'L' air brake restriction. She was tested two years ago in a tractor-trailer equipped with air-over-hydraulic brakes, and the examiner added the restriction.
461 words, about 2 min