Illinois CDL Combination case studies
Illinois CDL Combination · Put your knowledge to work in context.
The Illinois CDL Combination Vehicles knowledge test is the written exam a driver must pass to add the Class A combination-vehicle endorsement to an Illinois commercial driver's license. It is aimed at drivers who will operate a tractor-trailer, a truck towing a heavy trailer, or any power unit pulling one or more trailers with a gross combination weight rating over 26,000 pounds, and it is also required for drivers who need the combination endorsement on a Class B or C license. The Illinois CDL Combination case studies are 5 cases and about 3,020 words.
1The Rig That Leaks 5 psi a Minute
You are doing the air-brake portion of a pre-trip on a 3-axle tractor pulling a 53-foot van with a dual-circuit air system. Pressure builds to the governor cut-out at 128 psi and the compressor cuts back in at 105 psi.
575 words, about 3 min2The Fifth Wheel That Never Snapped Shut
You are picking up a 53-foot dry van loaded to 41,000 pounds. It sits on a paved lot with a slight nose-up slope, and the previous driver cranked the landing gear high - with your tractor centered on the trailer, the kingpin sits roughly two inches above the fifth wheel plate.
613 words, about 3 min3Right Turn, One Pole, One Impatient Car
You are driving a 3-axle tractor with a 53-foot van - about 70 feet bumper to tail - on a 30 mph city street with two lanes in your direction. You need to turn right onto a two-lane street.
626 words, about 3 min4Six Percent, Wet Pavement, Empty Trailer
You are descending a 6 percent grade on a wet two-lane highway in an empty 53-foot van. The trailer weighs about 13,000 pounds behind a 3-axle tractor; gross weight is under 40,000.
599 words, about 3 min5Two Tracks, a Hump, and a Backed-Up Light
You are westbound on a two-lane road in a 72-foot combination - 3-axle tractor, 53-foot van, loaded to about 78,000 pounds gross. One hundred feet ahead is a railroad crossing with two tracks, flashing lights, gates, and a humped profile where the rails sit about 4 inches above the pavement; the trailer's rear frame is low enough that the ramp angle matters.
607 words, about 3 min