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Colorado General Knowledge CDL Practice Test

Below are 25 exam-style questions for the Colorado General Knowledge CDL knowledge test, modeled on the FMCSA-aligned content used by the Colorado Department of Revenue Division of Motor Vehicles. Try to answer each question on your own before reading the answer key directly under it. The questions and answer choices are shuffled deterministically per state and endorsement, so the order will stay the same on repeat visits — that lets you genuinely measure your improvement.

Heads up: this is a study tool, not a graded exam. Cover the answer with your hand or a sheet of paper for an honest practice run, then re-read the explanations for any questions you missed. Aim for 22 out of 25 or better, three times in a row, before scheduling the real exam.
Question 1 of 25
A driver should test the parking brake by:
  • A Driving over a speed bump
  • B Pumping the brakes
  • C Releasing the parking brake on a flat surface and tugging gently against it
  • D Setting the parking brake, releasing the service brakes, and gently trying to move the vehicle in low gear
Correct answer: D
The standard test: set parking brakes, gently apply throttle in low gear; if the vehicle moves, the parking brake is not holding.
Question 2 of 25
When approaching a railroad crossing in a CMV that is not required to stop, you should:
  • A Always come to a full stop regardless of traffic
  • B Honk and proceed
  • C Slow down, look, listen, and be prepared to stop
  • D Cross at maximum speed to get over quickly
Correct answer: C
Even when not required by class to stop, you must always be prepared to stop. Buses, hazmat, and certain other vehicles must stop every time.
Question 3 of 25
You are driving on a two-lane road and you see a driver about to pull out from a side road. You should:
  • A Move to the right lane
  • B Cover the brake and slow down
  • C Honk and accelerate
  • D Maintain speed
Correct answer: B
Anticipate the worst-case behavior. Cover the brake — keeping your foot just over it — so you can react if they pull out.
Question 4 of 25
Stopping distance is made up of:
  • A Perception distance + reaction distance + brake-lag distance + braking distance
  • B Brake-lag distance only
  • C Speed times weight
  • D Reaction distance only
Correct answer: A
Total stopping distance has four parts. Air brakes add a brake-lag distance not present in hydraulic systems.
Question 5 of 25
Black ice is most likely on:
  • A Roads in direct sunlight
  • B Concrete pavement only
  • C Bridges and overpasses
  • D Gravel surfaces
Correct answer: C
Bridges and overpasses freeze first because cold air circulates above and below them. They are the most-asked test scenario for sudden ice.
Question 6 of 25
What is the most important reason for doing a vehicle inspection?
  • A To improve fuel economy
  • B To meet your dispatcher's schedule
  • C To reduce tire wear
  • D Safety for yourself and other road users
Correct answer: D
Federal rules and the FMCSA model manual list safety as the single most important reason for a pre-trip inspection. Mechanical defects discovered before the trip cannot kill anyone on the highway.
Question 7 of 25
Which of the following is a valid reason to refuse a load?
  • A It would make you exceed federal hours-of-service rules
  • B It would push your weight over legal limits
  • C All of the above
  • D The cargo is not properly secured or placarded
Correct answer: C
A driver is required by federal law to refuse loads that violate HOS, weight, or hazmat rules. The driver, not the dispatcher, is liable.
Question 8 of 25
Hours-of-service records are required to be kept by:
  • A No one
  • B The dispatcher only
  • C The carrier only
  • D The driver, in the form of a logbook or electronic logging device
Correct answer: D
Drivers are responsible for accurate hours-of-service records, kept either on paper logs or, for most carriers, on an ELD.
Question 9 of 25
Hydroplaning is most likely when:
  • A You brake hard on dry pavement
  • B Roads are dry but hot
  • C Tires lose contact with the road on a film of water
  • D Tires are over-inflated
Correct answer: C
Hydroplaning happens when tires ride on top of standing water at speed. Reduce risk by slowing down, keeping tires properly inflated and tread depth adequate.
Question 10 of 25
Engine retarders (Jake brakes) should be turned off when:
  • A On any downgrade
  • B Roads are wet, icy, or snow-covered
  • C In residential areas only because of noise
  • D Driving in dry conditions
Correct answer: B
Retarders can cause drive-wheel skids on slippery surfaces. Turn them off when traction is reduced.
Question 11 of 25
You are driving a heavy vehicle and have to stop on a long downgrade. Which is the safest way?
  • A Pump the brakes hard and fast
  • B Disengage the clutch and coast
  • C Use a low gear and steady moderate brake application
  • D Use the parking brake to slow down
Correct answer: C
On a long downgrade, select a low gear before the descent and use steady, light to moderate braking. Hard pumping or coasting in neutral leads to brake fade and loss of control.
Question 12 of 25
Which of the following is NOT part of a pre-trip inspection?
  • A Adjusting the trailer brakes individually
  • B Walking around the vehicle and checking lights
  • C Testing the service and parking brakes
  • D Checking the engine compartment
Correct answer: A
Adjusting brakes is a maintenance task done by qualified personnel, not a pre-trip step. The driver checks for proper operation, not adjustment.
Question 13 of 25
A driver who has lost the ability to safely brake the vehicle on a downgrade should:
  • A Look for an escape ramp
  • B Shift into reverse
  • C Coast in neutral
  • D Use the parking brake hard
Correct answer: A
Long downgrades have escape ramps for runaway trucks. Use them. Coasting in neutral is illegal in many states and worsens the problem.
Question 14 of 25
The minimum tread depth for steer-axle tires is:
  • A 4/32 inch
  • B 2/32 inch
  • C 1/32 inch
  • D 6/32 inch
Correct answer: A
Steer tires must have at least 4/32 inch in every major groove. Other tires require at least 2/32 inch.
Question 15 of 25
When the road is slippery, you should:
  • A Slow down
  • B Increase following distance
  • C Make smooth steering and braking inputs
  • D All of the above
Correct answer: D
Slippery roads require all three: more cushion, smoother inputs, and lower speed.
Question 16 of 25
When checking the engine compartment, you should make sure that:
  • A Engine oil level is safe to operate
  • B Power steering fluid is at the proper level
  • C All of the above
  • D Coolant level is above LOW and the cap is secure
Correct answer: C
A proper engine-compartment check covers oil, coolant, power steering fluid, windshield washer fluid, hoses, belts, and electrical wiring. Skipping any one of them defeats the purpose of the inspection.
Question 17 of 25
What does it mean when a road sign says "Bridge formation may freeze before road"?
  • A The bridge is closed in winter
  • B Bridges are inspected only in winter
  • C The pavement under the bridge is reinforced
  • D Bridge surfaces freeze first because of air circulation underneath
Correct answer: D
Cold air around bridges and overpasses cools the deck more quickly than the surrounding road, which is why ice often appears there first.
Question 18 of 25
When should you use four-way flashers?
  • A Only at night
  • B Only on the highway
  • C Whenever you feel like it
  • D When you are stopped or moving slowly enough to be a hazard
Correct answer: D
Four-ways are for vehicles stopped on or near the road or moving so slowly that they are a hazard.
Question 19 of 25
When driving at night, you should adjust speed so that you can stop within:
  • A The full range of high-beam headlights when in use
  • B The range of your low-beam headlights
  • C Whatever speed feels safe
  • D Half the range of your low-beam headlights
Correct answer: B
Always be able to stop within the distance you can see. At night with low beams, that's typically about 250 feet.
Question 20 of 25
A controlled braking technique means:
  • A Locking the wheels
  • B Coasting in neutral
  • C Pumping the brakes hard and fast
  • D Applying the brakes as hard as possible without locking the wheels
Correct answer: D
Controlled braking applies brakes hard but stops short of wheel lock-up. With ABS, you can simply press and hold full pressure.
Question 21 of 25
The proper following distance for a 60-foot truck traveling under 40 mph is at least:
  • A 4 seconds
  • B 6 seconds
  • C 1 second
  • D 10 seconds
Correct answer: B
Use one second per 10 feet of vehicle length below 40 mph: 60 ft / 10 = 6 seconds. Add one additional second above 40 mph.
Question 22 of 25
A driver's blood-alcohol concentration (BAC) of 0.04% or higher while operating a commercial motor vehicle is:
  • A A traffic violation, but not a CDL disqualification
  • B Considered driving under the influence for CDL purposes
  • C Allowed if the driver feels fine
  • D Allowed off-duty only
Correct answer: B
Federal rules treat 0.04% BAC in a CMV as DUI for CDL purposes — half the typical 0.08% limit for non-commercial drivers.
Question 23 of 25
A driver may keep moving when:
  • A Required emergency equipment is missing
  • B A vehicle is in safe operating condition
  • C A trailer brake light is out
  • D A passenger door is open
Correct answer: B
Federal rules forbid driving any CMV that is not in safe operating condition. Continue only after the defect is fixed.
Question 24 of 25
A vehicle's "no-zone" is:
  • A The fuel tank area
  • B The area in front of the steer axle
  • C The area immediately next to it where other drivers are hidden in your blind spots
  • D A federal speed restriction
Correct answer: C
No-zones are the four blind-spot areas (front, rear, and both sides) where smaller vehicles are difficult or impossible to see in your mirrors.
Question 25 of 25
A driver must report any accident involving a CMV to the carrier within:
  • A A reasonable time, before going off duty
  • B 7 days
  • C 24 hours
  • D 1 hour
Correct answer: A
FMCSA rules require notification of the motor carrier in a reasonable time — most policies treat that as before going off duty.

Study tips for the Colorado General Knowledge exam

The General Knowledge portion of the Colorado CDL exam is graded out of the bank of questions the Colorado Department of Revenue Division of Motor Vehicles draws from each year. While the exact bank is not published, every question is sourced from the General Knowledge chapter of the Colorado CDL handbook, which itself is derived from the FMCSA Model Commercial Driver's License Manual. That means studying our practice tests, reading the corresponding handbook chapter, and re-reading the parts you got wrong is genuinely the most efficient route to a first-time pass.

Most successful applicants follow a simple cycle: take the practice test cold, write down every question you missed, open the matching chapter of the official Colorado handbook, re-read the section that contains the right answer, then re-take the practice test 24 to 48 hours later. The 24-hour delay matters — sleep is when your brain commits new information to long-term memory, and CDL knowledge questions reward that kind of consolidated learning rather than cramming.

Pay particular attention to questions that include qualifier words like always, never, only, primary, or most. CDL test writers love to flip the right answer with a single qualifier. When two answer choices look almost identical, pay attention to the verb (is it must, should, or may?) and to any numbers (14 days, 100 air miles, 8 hours, 70/8 split). On endorsement tests in particular, watch for trick framing where a true statement about a different endorsement is offered as the "correct" answer to a question that is actually about General Knowledge.

Test-day logistics matter too. Bring photo ID, your Social Security card or birth certificate, your medical examiner's certificate (DOT card), and proof of state residency if you haven't already submitted those documents. The Colorado Department of Revenue Division of Motor Vehicles will not let you sit for the knowledge exam without your documentation, and most offices charge an additional fee for re-attempts. Arrive early — the wait at most CDL testing offices runs 30 to 60 minutes — and silence your phone before the exam begins.

Finally, keep your General Knowledge fundamentals sharp even when you're focused on the General Knowledge exam. Many states administer multiple knowledge tests in a single sitting, and questions on weight definitions (GVWR, GCWR, GAWR), stopping distance, and the pre-trip inspection routine show up across endorsements. If you're unsure on the basics, sit a fresh Colorado General Knowledge practice test before scheduling the real exam.

Next steps

Missed more than four questions? Re-read the General Knowledge study guide and the matching chapter in the official Colorado CDL handbook. Then come back and re-take the test. Once you can score 22 of 25 or higher on three runs in a row, you're in good shape to schedule the real exam at your local Colorado Department of Revenue Division of Motor Vehicles office.

Already comfortable with this endorsement? Drill another: CO Air Brakes · CO Combination Vehicles · CO Hazardous Materials · CO Passenger · CO School Bus · CO Tank Vehicle · CO Doubles / Triples

New to the CDL process in Colorado? Read How to apply for a CDL in Colorado for the document checklist and step-by-step timeline.