Alabama CDL Combination Vehicles case studies
Alabama CDL Combination Vehicles · Put your knowledge to work in context.
The Alabama CDL Combination Vehicles knowledge test is one of the endorsement-style written tests a driver must pass to obtain a Class A commercial driver license or to add combination-vehicle privileges. It is aimed at drivers who will operate tractor-trailers, doubles, triples, or other vehicles with a towed unit, where the trailer's weight and articulation change how the rig brakes, turns, and stops. The test covers the full working knowledge of a combination unit: pre-trip inspection of the coupling and air lines, the coupling and uncoupling sequence, air brake checks and the trailer protection valve, safe driving practices such as controlled speed on curves and proper following distance, turning and lane-change technique including offtracking and the swing of the rear trailer, backing and parking, and rollover prevention. Questions are multiple choice, and the test is drawn from the Alabama CDL manual, so the most reliable preparation is to read the combination vehicles and air brake sections closely, then practice with a question set that explains why each wrong answer is wrong. The Alabama CDL Combination Vehicles case studies are 5 cases and about 3,052 words.
1The Loaded Trailer That Won't Build Full Pressure
You are pre-tripping a tractor-trailer before a 5:00 a.m. The tractor is a 2019 day cab; the trailer is a 53-foot dry van loaded to about 42,000 lb.
544 words, about 3 min2Tight Right Turn With a Long Trailer
You are driving a 53-foot trailer with the tandems slid all the way back, turning right from a two-lane road onto a narrower two-lane road at a signalized intersection. The corner has a raised curb with a fire hydrant on the near right and a light pole on the far right corner.
521 words, about 3 min3Backing Into a Dock With a Blind-Side Approach
at a distribution center. You need to back a 53-foot trailer into dock 14, which is on your right.
684 words, about 3 min4Downhill Grade With a Full Load and Warm Brakes
You are descending a 6% grade that runs for about 4 miles. Your combination weighs roughly 78,000 lb.
616 words, about 3 min5Coupling to a Trailer With a High Fifth Wheel
You are coupling to a loaded trailer after a trailer swap. The tractor's fifth wheel is set high for a previous low trailer.
687 words, about 3 min