Illinois (IL) CDL manual 2026
Reading the manual is not the same as passing the test on it. Practice it instead: every chapter below has real test questions you can answer right here, plus what Illinois does its own way.
Practice the manual, chapter by chapter
State manuals are built on the same national model, chapter for chapter. One thing to know from each chapter, then real questions from it to answer — tap an option to check yourself.
- 1
Introduction
Everyone
You will lose your CDL for at least 60 days if you have committed two serious traffic violations within a three-year period involving a CMV.
This chapter has 26 more questions. Practice them in the app and see your pass chance.What is the penalty for a third railroad crossing violation within three years?
The sequence runs 60 days, then 120 days, then at least one year for the third violation inside a three-year period.
Manual section 1.3.5
How far above the posted limit counts as excessive speeding for a serious traffic violation?
Fifteen over is the line. Below it the ticket is an ordinary speeding offense rather than one of the serious violations that stack toward disqualification.
Manual section 1.3.3
- 2
Driving Safely
Everyone
That space can be very small when a vehicle is heavily loaded; this is often a problem on dirt roads and in unpaved yards.
This chapter has 290 more questions. Practice them in the app and see your pass chance.Why should you never change gears while your vehicle is moving across railroad tracks?
A gear change that fails on the crossing can leave the vehicle without power on the tracks, so drivers should cross in a gear that will carry them completely across without shifting.
Manual section 2.15
Which wheel components does the manual say are dangerous when missing?
Each of these holds the wheel assembly together. Any one of them missing puts the remaining hardware under load it was not designed to carry alone.
Manual section 2.1.3
- 3
Transporting Cargo Safely
Everyone
Overloading can have bad effects on steering, braking, and speed control.
This chapter has 26 more questions. Practice them in the app and see your pass chance.What does Gross Vehicle Weight Rating describe?
GVWR is a rating set by the manufacturer, not a measurement. It states how much the single vehicle is designed to weigh when loaded.
Manual section 3.2.1
Which cargo responsibility remains yours even when someone else loads the vehicle?
Inspecting the cargo, spotting overloads and bad balance, and knowing it is secured and not blocking your view or your emergency equipment all stay with the driver.
Manual section 3
- 4
Transporting Passengers
P endorsement (bus)
Urban mass transit coaches may have a brake and accelerator interlock system.
This chapter has 98 more questions. Practice them in the app and see your pass chance.Your coach is low on fuel mid-trip and a truck stop is ahead. What is the general rule about refueling while your passengers remain in their seats?
Fueling a bus with riders aboard should be avoided unless it is truly necessary, because fuel handling creates a fire risk close to the passengers.
Manual section 4.4
You are driving a bus toward a railroad crossing where a stop is required. Within what distance range before the nearest rail must you stop?
Buses must stop between 15 and 50 feet before the nearest rail at railroad crossings where a stop is required. From there the driver looks and listens in both directions for a train.
Manual section 4.3
- 5
Air Brakes
Any vehicle with air brakes
Spring brakes activate at 20 to 45 psi, typically 20 to 30 psi.
This chapter has 147 more questions. Practice them in the app and see your pass chance.How is the cab control for a front brake limiting valve normally marked?
The two positions are labeled normal and slippery, reflecting the mistaken belief that cutting front brake pressure helped on poor surfaces.
Manual section 5.1.13
How do the brake lights come on when you apply the brakes on a vehicle with air brakes?
Air brake vehicles use an electric stop light switch that is operated by air pressure; applying the brakes sends air through the switch, which turns on the brake lights.
Manual section 5.1.12
- 6
Combination Vehicles
Class A
The tractor must be lined up directly in front of the trailer before backing under; never back under at an angle.
This chapter has 118 more questions. Practice them in the app and see your pass chance.Why is a fully loaded tractor-trailer more likely to roll over in a curve than a passenger car?
The higher a vehicle's center of gravity sits, the more easily it tips in a curve, and a loaded combination carries much of its weight well above the roadway.
Manual section 6.1.1
What steering habit best protects a doubles driver from tipping the rear trailer through rearward amplification?
Gentle, gradual steering keeps the motion transferred to the trailers small, preventing the amplified swing that can tip the rearmost unit.
Manual section 6.1.2
- 7
Doubles and Triples
T endorsement
Triples exhibit the greatest rearward amplification among common combinations.
This chapter has 98 more questions. Practice them in the app and see your pass chance.A converter dolly has no spring brakes. How do you release its brakes so it can be moved into position?
On a dolly without spring brakes, the brakes are held on by air stored in its tank. Opening the tank petcock bleeds that air off and frees the wheels.
Manual section 7.2.1
When hooking air lines between the first trailer and the converter dolly, how do you avoid crossing them?
Service and emergency lines are color coded, commonly blue for service and red for emergency, so matching like to like prevents crossed lines.
Manual section 7.2
- 8
Tank Vehicles
N endorsement
Side-to-side surge in curves adds lateral force that raises rollover risk in tank vehicles.
This chapter has 62 more questions. Practice them in the app and see your pass chance.A tanker driver wants to avoid skids, which are especially dangerous when a liquid load is pushing on the tank. What causes most skids?
Most skids happen when a driver is going too fast for conditions and then brakes, steers, or accelerates harder than the available traction allows.
Manual section 8.3
During a pre-trip inspection of a cargo tank, what is the most important thing to check the tank body, piping, and valves for?
The single most important tank inspection item is checking for leaks. It is illegal and dangerous to transport cargo in a leaking tank, and the driver can be cited and shut down for doing so.
Manual section 8.1
- 9
Hazardous Materials
H endorsement
The only acceptable way to check tire pressure is to use a tire pressure gauge.
This chapter has 234 more questions. Practice them in the app and see your pass chance.What does the manual require for materials subject to spontaneous combustion or heating?
Ventilation carries away the heat and vapor these materials generate. Without it the cargo space becomes the very environment that starts the fire.
Manual section 9.4.1
Within what period must carriers make detailed written reports of a hazardous materials incident?
The phone call to the National Response Center is immediate; the carrier's detailed written report follows within 30 days.
Manual section 9.7.5
- 10
School Buses
S endorsement
Position the overhead inside rearview mirror to see the top of the rear window in the top of the mirror and all of the students, including the heads of the students right behind you.
This chapter has 98 more questions. Practice them in the app and see your pass chance.How far can the blind spot behind a school bus extend, depending on the bus's size?
The rear blind spot runs from roughly 50 to 150 feet and can reach 400 feet on a longer, wider bus. Nothing in that space is visible without the side mirrors.
Manual section 10.1.3
How should students board the bus?
Single file at a walking pace with a hand on the rail is what keeps a child from being pushed off the steps or caught in the door.
Manual section 10.2.2
- 11
Pre-Trip Vehicle Inspection
Everyone (skills test)
Make sure that valve caps are not missing, and valve stems are not damaged or broken.
This chapter has 200 more questions. Practice them in the app and see your pass chance.With the engine in what state are the critical fluid levels inspected?
The fluids are checked with the engine off, which is also why the caution about the radiator cap applies.
Manual section 11.5.1
What do rust streaks or shiny metal trails radiating out from a wheel's lug nuts usually indicate?
Rust trails or shiny streaks spreading from lug nuts are a warning sign that the nuts have loosened and the wheel is moving slightly on its studs.
Manual section 11.2.5
What’s different in Illinois
Most of every state manual is the same federal material. These are the parts that are not.
- Low air warning in the air brakes chapter (written test): before pressure drops below 60 psi.
- A warning signal you can see must come on before the air pressure in the tanks falls below 60 psi (or one-half the compressor governor cut-out pressure on older vehicles).
- No vehicle other than a semitrailer shall exceed a length of 42 feet; semitrailers may have an overall length of 53 feet, including the load.
The official Illinois CDL manual
Published free by Illinois Secretary of State, Driver Services Department
On their site, search for “CDL manual” to download the latest edition.