OR CDL Combination study plan

Memorize the full sequence for a complete combination-vehicle pre-trip inspection, naming each zone and what to check in it from memory without notes

State the correct order of steps for coupling a tractor to a semi-trailer, including the tug test and the visual fifth-wheel jaw check

Identify the parts of the air brake system on a combination vehicle (compressor, governor, reservoirs, foot valve, relay valve, spring brakes, slack adjusters) and explain what each does

Perform and narrate a static air-brake check: applied-leakage, tractor/trailer protection-valve test, and low-pressure warning activation

Demonstrate the uncoupling sequence in order, including landing gear, air line and electrical line removal, and pulling clear of the trailer

Explain why the trailer spring brakes must be set and the tractor protection valve closed before uncoupling, and what happens if they are not

Adjust a slack adjuster check: describe the pushrod stroke measurement method and the legal/out-of-service limit concept

Diagnose three written fault scenarios (e.g., trailer brakes will not release, low air warning fails to sound) and state the correct response and whether the vehicle may be driven

Describe the correct technique for a right turn in a combination vehicle, including swing-out, off-tracking, and when to check mirrors

Calculate and explain the difference between the path of the tractor rear wheels and the trailer rear wheels in a tight turn

List the conditions that cause a rearward (trailer) jackknife and the driver actions that prevent it

Explain how speed, center of gravity, and load height combine to cause a rollover, and state the safe speed rule for curves

Apply the four-second following-distance rule and the total stopping-distance formula for a loaded combination vehicle at highway speed

Explain proper braking technique on downgrades, including the role of engine braking and why continuous light braking is dangerous

Describe the correct response to a trailer skid, including what to do and what not to do with the steering wheel and brakes

Identify the conditions requiring a reduced speed (rain, fog, curves, heavy traffic, off-ramps) and state a specific target speed for each

State the working load limit concept and explain how to determine the number of tiedowns required for a given load weight and length

Explain weight distribution: gross vehicle weight, axle weight limits, and the effect of placing cargo too far forward or too far back on steering and trailer sway

Describe the correct use of tiedowns, binders, and edge protection, and list the common securement failures that cause load loss

Explain trailer handling basics: sliding the tandem axles to adjust weight distribution and the effect on kingpin load

Perform a cargo securement inspection checklist from memory: tiedown count, tension, edge protection, and load integrity

Explain how an improperly loaded trailer changes braking distance and rollover risk, connecting weight distribution to domains 3 and 4

Re-run the coupling sequence with a focus on the air line and electrical line connection order and the consequences of a crossed or unconnected line

Describe the pre-trip items specific to a loaded trailer, including brakes, lights, mud flaps, and landing gear position

Complete a full timed air-brake check sequence (static leakage, protection valve, low-pressure warning, and compressor build-up) and state each pass/fail criterion

Explain the causes and prevention of front-wheel skids, rear-wheel skids, and trailer swing, and the steering and braking response for each

Describe the correct procedure for a brake failure on a downgrade, including use of the emergency/parking brake and runaway ramp

Explain how to recover from a jackknife or sway event without overcorrecting

Take two full-length timed practice exams under test conditions and review every missed question until you can explain the correct answer

Re-narrate the complete pre-trip, coupling, and uncoupling sequences from memory without notes

Recite the key numbers from memory: following distance, stopping distance, low-air warning threshold, and tiedown requirements

Identify your two weakest domains from practice-exam data and drill 15 targeted questions in each