Missouri General Knowledge CDL Practice Test
25 realistic General Knowledge practice questions for Missouri CDL applicants. Required for: All CDL applicants (Class A, B, and C). Official test: 50 questions, 40 correct to pass.
Question 1 of 25 · Hazard Awareness
How can you tell if your truck or bus has a hazardous materials shipment?
-
A.
It is moving slowly
-
B.
Diamond-shaped placards are displayed
-
C.
A flashing yellow light is on
-
D.
It is following another truck
Correct answer: B.
Diamond-shaped placards on the vehicle indicate the presence of hazardous materials.
Question 2 of 25 · Testing
The road test will be scored on:
-
A.
How fast you complete the route
-
B.
Vehicle inspection, basic control, and on-road driving
-
C.
Whether you wear a uniform
-
D.
Your appearance
Correct answer: B.
You'll be evaluated on inspection skills, basic control skills, and safe on-road driving performance.
Question 3 of 25 · Emergency Equipment
What three kinds of emergency equipment must you have in your vehicle?
-
A.
Spare tire, fuses, and reflective triangles
-
B.
Fire extinguisher, spare fuses (if equipped), and warning devices
-
C.
First aid kit, water, and flares
-
D.
Tool kit, fuel can, and flag
Correct answer: B.
You must have a fire extinguisher, spare electrical fuses (if equipped), and warning devices for stopped vehicles.
Question 4 of 25 · Driver Wellness
What should you do when an aggressive driver confronts you?
-
A.
Make eye contact and respond
-
B.
Try to escape the situation safely and avoid eye contact
-
C.
Slow down to teach a lesson
-
D.
Speed up and pass
Correct answer: B.
Avoid engagement, give space, do not make eye contact, and report the behavior.
Question 5 of 25 · Speed Management
When approaching a curve, you should:
-
A.
Brake while in the curve
-
B.
Slow down before entering the curve
-
C.
Maintain highway speed
-
D.
Use the engine brake throughout
Correct answer: B.
Reduce speed before entering the curve, then accelerate slightly through the curve for stability.
Question 6 of 25 · Communication
Communicating your intentions means:
-
A.
Honking before each turn
-
B.
Using turn signals, brake lights, and the horn appropriately
-
C.
Flashing high beams at all drivers
-
D.
Hand signals only at intersections
Correct answer: B.
Use signals, brake lights, and the horn properly to communicate. Hand signals supplement them.
Question 7 of 25 · Basic Control
You should use the parking brake:
-
A.
Only when parking on hills
-
B.
Whenever you leave the vehicle
-
C.
Only when leaving the engine running
-
D.
Only on slick surfaces
Correct answer: B.
Always set the parking brake whenever you leave your vehicle, regardless of the surface or grade.
Question 8 of 25 · Backing
The most important hand signal you and a helper should agree on is:
-
A.
Speed up
-
B.
Stop
-
C.
Turn left
-
D.
Back straight
Correct answer: B.
Always agree on a clear stop signal before backing. The helper must be able to stop you instantly.
Question 9 of 25 · Hours of Service
How often must a driver complete a written record of duty status?
-
A.
Every 8 hours
-
B.
Every 12 hours
-
C.
Every 24 hours
-
D.
Once a week
Correct answer: C.
A daily record of duty status (logbook) must be completed each 24-hour period.
Question 10 of 25 · CDL Rules
Refusing a chemical test for alcohol or drugs while operating a CMV will result in:
-
A.
A warning
-
B.
A 90-day suspension
-
C.
CDL disqualification of at least one year
-
D.
A simple fine
Correct answer: C.
Refusal is treated the same as testing positive — minimum one-year disqualification.
Question 11 of 25 · Mountain Driving
What may happen if you don't shift gears properly when going up a hill?
-
A.
You will use less fuel
-
B.
The transmission will be damaged
-
C.
You may lose control on a downgrade
-
D.
Engine RPM will be too low
Correct answer: C.
Improper gear use can result in losing control of speed, especially on the way back down a hill.
Question 12 of 25 · Night Driving
You should use low beam headlights:
-
A.
Whenever you can
-
B.
Within 500 feet of an oncoming vehicle and 500 feet behind another vehicle
-
C.
Only in fog
-
D.
On lighted city streets only
Correct answer: B.
Use low beams within 500 feet of oncoming traffic and when following within 500 feet of another vehicle.
Question 13 of 25 · Following Distance
Following distance for a heavy vehicle traveling below 40 mph should be at least:
-
A.
1 second per 10 feet of vehicle length
-
B.
Half the length of the vehicle
-
C.
Two seconds total
-
D.
No specific amount required
Correct answer: A.
Use one second of following distance for every 10 feet of vehicle length below 40 mph; add a second above 40 mph.
Question 14 of 25 · Emergency Maneuvers
Stab braking is used:
-
A.
Only on slippery roads
-
B.
When you must stop quickly with non-ABS brakes
-
C.
Whenever you stop
-
D.
Only on downgrades
Correct answer: B.
Stab braking is an emergency technique used with non-ABS brakes: apply brakes fully, release when wheels lock, then reapply.
Question 15 of 25 · Rail Crossings
When approaching a railroad crossing without flashing lights or gates, you should:
-
A.
Slow down, look, and listen for trains
-
B.
Always come to a complete stop
-
C.
Speed up to clear the crossing quickly
-
D.
Sound horn but maintain speed
Correct answer: A.
Without active warning devices, slow down and look and listen carefully for an approaching train.
Question 16 of 25 · Basic Control
Where should the wheel chocks be placed?
-
A.
Behind one tire
-
B.
In front of and behind tires on the same axle
-
C.
Only when on a hill
-
D.
Both front and rear tires of the steer axle
Correct answer: B.
Place chocks both in front of and behind the wheels to prevent the vehicle from rolling either way.
Question 17 of 25 · Emergency Equipment
Most heavy vehicle fires are caused by:
-
A.
Hot tires from low pressure or under-inflated duals
-
B.
Cold weather
-
C.
Engine cooling system
-
D.
Exhaust pipes only
Correct answer: A.
Hot tires and brakes are leading causes. Inspect tires and brakes regularly to prevent fires.
Question 18 of 25 · Driver Wellness
Which of the following affects alcohol absorption into the body?
-
A.
Drinking on a full stomach
-
B.
How fast you drink
-
C.
Body weight
-
D.
All of the above
Correct answer: D.
Stomach contents, drinking speed, and body weight all influence absorption.
Question 19 of 25 · Vehicle Dynamics
Empty trucks:
-
A.
Always stop more quickly than loaded trucks
-
B.
Have less traction because there is less weight on the drive axles
-
C.
Can take curves at higher speeds safely
-
D.
Are not affected by wind
Correct answer: B.
Empty trucks have reduced traction on drive axles and require greater stopping distances than loaded trucks.
Question 20 of 25 · Driver Wellness
Distracted driving includes:
-
A.
Talking on a hand-held cell phone
-
B.
Eating
-
C.
Reading maps
-
D.
All of the above
Correct answer: D.
All of these activities take attention from driving and are forms of distracted driving.
Question 21 of 25 · Speed Management
When you double your speed, your stopping distance is multiplied by approximately:
-
A.
Two
-
B.
Three
-
C.
Four
-
D.
Six
Correct answer: C.
Stopping distance grows with the square of speed. Doubling speed roughly quadruples the distance needed to stop.
Question 22 of 25 · Emergency Maneuvers
Controlled braking is:
-
A.
Pressing the brake to the floor and holding
-
B.
Applying brakes hard enough to lock the wheels
-
C.
Applying brakes to keep wheels just short of locking
-
D.
Releasing brakes and coasting
Correct answer: C.
Controlled braking applies the brake firmly without locking the wheels, keeping the steering straight.
Question 23 of 25 · Night Driving
When meeting an oncoming vehicle at night, you should:
-
A.
Look directly at the headlights
-
B.
Look toward the right side of the road
-
C.
Switch to high beams
-
D.
Increase speed
Correct answer: B.
Look toward the right side of the road to avoid being blinded by oncoming headlights.
Question 24 of 25 · Adverse Conditions
Hydroplaning is most likely to occur when:
-
A.
Tires are properly inflated
-
B.
Speed is below 30 mph
-
C.
Roads are dry
-
D.
Tires lose contact with the road on wet pavement
Correct answer: D.
Hydroplaning happens when water builds up between the tire and the road, causing loss of contact.
Question 25 of 25 · Adverse Conditions
What should you do before driving in fog?
-
A.
Use high beams to see further
-
B.
Slow down and use low beams and fog lights if equipped
-
C.
Speed up to clear the fog area
-
D.
Follow another vehicle closely
Correct answer: B.
Slow down before entering fog. Use low beams and any installed fog lights.
About the General Knowledge Test
The General Knowledge test covers safe vehicle inspection, basic vehicle control, shifting gears, communicating, controlling speed, controlling distance, seeing hazards, distracted driving, aggressive drivers, communicating with other drivers, night driving, driving in fog, winter driving, hot weather driving, mountain driving, driving emergencies, anti-lock braking systems, skid recovery, accident procedures, fires, alcohol and other drugs, hazardous materials awareness, and staying alert and fit to drive. Every commercial driver in the United States must pass this test before any other CDL endorsement can be added.
The Missouri Department of Revenue — Driver License Bureau administers this knowledge test as part of its commercial driver license program. To earn the CDL General Knowledge on your Missouri CDL, you need to score at least 40 out of 50 on the official version.
Topics covered on this practice test
- Driver Wellness: 3 questions
- Emergency Equipment: 2 questions
- Speed Management: 2 questions
- Basic Control: 2 questions
- Night Driving: 2 questions
- Emergency Maneuvers: 2 questions
- Adverse Conditions: 2 questions
- Hazard Awareness: 1 question
- Testing: 1 question
- Communication: 1 question
- Backing: 1 question
- Hours of Service: 1 question
- CDL Rules: 1 question
- Mountain Driving: 1 question
- Following Distance: 1 question
- Rail Crossings: 1 question
- Vehicle Dynamics: 1 question
How to use this practice test
- Read each question carefully. CDL questions are written precisely — small wording differences matter.
- Click "Show Answers & Explanations" only after answering every question. Don't peek mid-test.
- Read the explanation for every question, even ones you got right. The reasoning is more important than the answer.
- Repeat the test until you score 100%. The questions are deterministic per state, so you can track your improvement over multiple sessions.
- Move on to the other endorsement tests for Missouri until you're ready for the official exam.
Tips specific to the General Knowledge test
The General Knowledge test is the foundation of every CDL. Topics include vehicle inspection, basic control, shifting, communicating, controlling speed, controlling space, hazard perception, distracted driving, night driving, fog, winter, hot weather, mountain driving, emergencies, anti-lock brakes, skid recovery, accident procedures, fires, alcohol, hazardous materials awareness, and staying alert. Most failures come from speeding through inspection-related questions; slow down and read carefully.
Other practice tests for Missouri