Michigan CDL Doubles/Triples case studies
Michigan CDL Doubles/Triples · Put your knowledge to work in context.
The Michigan CDL Doubles/Triples (T) endorsement is the add-on to a Class A commercial driver license that lets you legally pull two or three trailers behind a single tractor. Michigan trucking operations use it for LTL line-haul, auto-parts shuttles, and gravel or aggregate runs where a second or third pup trailer multiplies payload per driver. The Michigan CDL Doubles/Triples case studies are 5 cases and about 2,509 words.
1Coupling a Converter Dolly on a Sloped Yard
At a Detroit-area terminal, you are building a set of doubles. The tractor is already coupled to the first 28-foot trailer, which is parked on a paved yard with a 2–3% slope toward a chain-link fence.
636 words, about 3 min2Triple-Trailer Pre-Trip With Multiple Defects
You are assigned a triple-trailer set: three 28-foot pups, 80,000 lb gross, pulling out of a cold Michigan yard at 6:10 a.m. During the walk-around you find: the rear trailer's ABS lamp stays on after the ignition self-check; the middle trailer's left spring hanger has a fresh 3-inch crack; the tractor's air gauge drops from 105 to 99 psi in two minutes with the engine off and brakes released; and the converter dolly's safety chains are twisted but not broken.
486 words, about 2 min3Emergency Line Leak and Chafed Electrical Cord
After coupling a set of doubles at a truck stop, you notice the blue emergency line at the dolly's gladhand is not seated squarely; it leaks enough that the tractor's gauge falls from 100 to 92 psi in 90 seconds with the engine off and the brakes released. The electrical cord to the rear trailer is chafed through the outer jacket, exposing two insulated wires, and the rear trailer's ABS lamp stays on.
484 words, about 2 min4Triple-Trailer Downhill With Brake Fade
You are pulling a 75-foot triple-trailer set at 78,500 lb on a 6-mile, 6% downgrade marked 'Steep 6 miles.' The posted truck speed is 35 mph. At the top, your speed is 50 mph in 8th gear; the engine brake is on high, but you have not used the trailer brakes.
469 words, about 2 min5Lane Change, Low Bridge, and Tight Turn With Triples
You are pulling 28-foot triple pups, 80,000 lb gross, eastbound on a 4-lane divided highway with a 65-mph limit and a 15-mph crosswind from the right. You need to move from the right lane to the left lane to avoid a disabled truck on the shoulder.
434 words, about 2 min