Florida CDL — General Knowledge Practice Test
50 questions · pass with 40 correct. You get instant feedback and an explanation after every answer.
Florida CDL — General Knowledge questions with answers
20 sample questions from the Florida CDL — General Knowledge question bank — each with the correct answer, a short explanation, and the section of the official handbook it comes from.
1. A roadside inspector places your vehicle 'out of service.' What does that mean?
Correct answer: The vehicle must not be driven until the problem is corrected
An out-of-service order means the vehicle (or driver) has a serious safety violation and may not be driven until it is corrected. Ignoring an out-of-service order brings heavy fines and disqualification.
Source: Florida CDL Handbook — Disqualifications and Penalties
2. Objects seen in a convex ('spot') mirror on a truck appear:
Correct answer: Smaller and farther away than they really are
Convex mirrors show a wider area but make everything look smaller and farther away than it really is. A vehicle in a convex mirror is closer and larger than it appears.
Source: Florida CDL Handbook — Seeing
3. Your right wheels drift off onto the dirt shoulder. What is the safest way to get back on the road?
Correct answer: Ease off the gas, keep straight, slow down, then steer back gently
Stay off the brake, ease off the accelerator, and keep the vehicle straight until it slows. When it is safe and your speed is down, steer back onto the pavement gently — do not jerk the wheel.
4. How should a commercial driver approach a highway work zone?
Correct answer: Slow down, obey the reduced limit, and watch for workers
Slow down, obey the posted work-zone speed, watch for workers and sudden stops, and be ready for lane shifts. Fines for speeding in a work zone are typically increased.
5. How far ahead should a commercial driver normally look while driving?
Correct answer: About 12 to 15 seconds ahead
Looking 12 to 15 seconds ahead — about a block or more in the city and a quarter mile on the highway — lets you spot hazards early and react smoothly instead of at the last second.
6. Why should a driver pay attention to the space above the vehicle?
Correct answer: Low clearances can strike the top of the vehicle if you do not check your height
Low bridges, signs, and wires can be lower than they look, and a loaded or air-suspension vehicle's height can change. Know your height and watch posted clearances to avoid striking overhead objects.
7. Under implied-consent rules, what have you agreed to by driving a commercial vehicle?
Correct answer: You agree to submit to alcohol or drug testing when asked
By driving, you have already agreed to be tested for alcohol or drugs when lawfully asked. Refusing the test brings the same kind of penalty as failing it.
Source: Florida CDL Handbook — Alcohol, Other Drugs, and Driving
8. A sign posting a clearance such as '12 FT 6 IN' at an underpass means a driver should:
Correct answer: Make sure the vehicle's height is under that clearance before proceeding
That number is the overhead clearance. If your loaded vehicle is taller than the posted height, you must not drive under it — find another route to avoid striking the structure.
9. You have to stop your commercial vehicle on the shoulder of a highway. What should you do?
Correct answer: Pull as far off as possible, turn on flashers, and set out warning triangles
Get as far off the road as you can, turn on your four-way flashers, and set out your emergency warning devices (reflective triangles) so approaching drivers see you in time.
10. Which action would violate the federal handheld-phone rule for a commercial driver?
Correct answer: Holding the phone to your ear to make a call
Holding a phone to dial or talk, or reaching for one in an unsafe position, is prohibited for CMV drivers. Hands-free use — a mounted phone, one-button answering, or a headset — is allowed, and texting is never allowed.
11. What can happen to a CDL holder who repeatedly texts or uses a handheld phone while driving a CMV?
Correct answer: Fines and, after multiple offenses, disqualification of the CDL
Federal rules treat texting and handheld phone use as serious violations. They carry fines for the driver and the employer, and two or more offenses within a set period lead to disqualification of the CDL.
Source: Florida CDL Handbook — Disqualifications and Penalties
12. You are about to slow down where drivers behind may not expect it. How can you warn them?
Correct answer: Tap the brake pedal to flash your brake lights and use flashers if needed
Tap the brake pedal a few times to flash your brake lights, and use the four-way flashers if you must travel much slower than surrounding traffic. This warns drivers who might otherwise close in fast.
13. What do antilock braking systems (ABS) help a driver do?
Correct answer: Keep the wheels from locking so you can steer while braking hard
ABS keeps the wheels from locking up during hard braking so you can steer and stay in control. It does not necessarily stop you sooner — its job is to help you keep control while braking.
14. Which vehicles are generally required to stop at every railroad crossing, even when no train is coming?
Correct answer: Buses carrying passengers and trucks hauling placarded hazardous materials
Certain vehicles — such as buses carrying passengers and trucks placarded for hazardous materials — must stop at railroad crossings, check that the way is clear, and then cross without shifting gears.
15. In cold weather, how can a driver get an early clue that the road may be icing over?
Correct answer: Watch for ice building up on mirrors, wipers, or antennas, and for spray from other tires stopping
Ice forming on mirror arms, wipers, or the antenna is a warning that surfaces are freezing. When tire spray from other vehicles stops even though the road looks wet, the water may be turning to ice — slow down.
16. Compared with a fully loaded truck, an empty truck often needs:
Correct answer: A longer stopping distance because of reduced traction
Empty trucks can take longer to stop because their brakes and tires are designed to grip best under a heavy load. With little weight, the tires have less traction and can lock up more easily.
17. Which statement about other drugs and driving a CMV is correct?
Correct answer: Prescription and over-the-counter drugs can also impair driving
Many prescription and over-the-counter medicines — such as some cold or allergy pills — cause drowsiness or slow reactions. Do not drive on any drug that impairs you, and follow the law and your employer's rules.
Source: Florida CDL Handbook — Alcohol, Other Drugs, and Driving
18. A round yellow sign with a black 'X' and the letters 'RR' means:
Correct answer: A railroad crossing is ahead, so slow down and be ready to stop
The round yellow sign with the black 'X' and 'RR' is the advance warning for a railroad crossing. It tells you to slow down, look, listen, and be prepared to stop for a train.
19. Whenever you park and leave a commercial vehicle, you should always:
Correct answer: Set the parking brake and secure it against rolling
Set the parking brake and, on a grade, chock the wheels or turn them toward the curb so the vehicle cannot roll. A heavy vehicle that rolls away can cause serious damage.
Source: Florida CDL Handbook — Basic Control of Your Vehicle
20. Under current federal rules, how may a CDL driver legally use a mobile phone while driving a commercial motor vehicle?
Correct answer: Only hands-free, without holding, dialing, or reaching for the phone
Federal rules bar holding, dialing, or reaching for a handheld phone while driving a CMV. You may only make a call hands-free, using a device that lets you press a single button while staying properly seated and belted. Violations bring fines and can lead to disqualification.