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Oklahoma General Knowledge CDL Practice Test

Below are 25 exam-style questions for the Oklahoma General Knowledge CDL knowledge test, modeled on the FMCSA-aligned content used by the Oklahoma Department of Public Safety. 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
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 Half the range of your low-beam headlights
  • D Whatever speed feels safe
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 2 of 25
Which is true about the use of turn signals?
  • A Signal only when other vehicles are present
  • B Use the four-way flashers instead of signals at intersections
  • C Signal only at the moment you start turning
  • D Signal early, signal continuously, and cancel after the turn
Correct answer: D
The federal model manual specifies signal early, continuously, and cancel after — the same three steps every state CDL test asks about.
Question 3 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 Use the parking brake to slow down
  • C Disengage the clutch and coast
  • D Use a low gear and steady moderate brake application
Correct answer: D
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 4 of 25
What is the most important reason for doing a vehicle inspection?
  • A Safety for yourself and other road users
  • B To meet your dispatcher's schedule
  • C To improve fuel economy
  • D To reduce tire wear
Correct answer: A
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 5 of 25
The minimum tread depth for steer-axle tires is:
  • A 2/32 inch
  • B 6/32 inch
  • C 1/32 inch
  • D 4/32 inch
Correct answer: D
Steer tires must have at least 4/32 inch in every major groove. Other tires require at least 2/32 inch.
Question 6 of 25
Drivers may not drive after being on duty:
  • A 15 hours of driving
  • B 8 hours in any 24-hour period
  • C 14 consecutive hours since coming on duty
  • D 20 hours in a 24-hour period
Correct answer: C
The 14-hour rule limits the on-duty window during which up to 11 hours of driving may occur.
Question 7 of 25
Cargo that hangs more than 4 feet beyond the back of the vehicle must be marked with:
  • A A green flag
  • B Nothing — federal rules do not require marking
  • C Yellow tape only
  • D A red flag (or red light at night) at the extreme rear
Correct answer: D
Federal rules require a red flag during the day and red lights at night for projecting cargo beyond 4 feet.
Question 8 of 25
When should you do an en-route inspection?
  • A Only if a warning light comes on
  • B Within the first 25 miles, then about every 150 miles or every 3 hours
  • C Only when the load is hazardous
  • D At the end of the trip
Correct answer: B
The FMCSA model manual recommends a check within the first 25 miles to catch loose cargo or under-inflated tires that have warmed up, then about every 150 miles or 3 hours, and any time you stop.
Question 9 of 25
The proper response to a tire blowout on the front axle is to:
  • A Hold the steering wheel firmly, ease off the accelerator, and let the vehicle slow down
  • B Brake immediately and pull off the road
  • C Steer sharply toward the shoulder
  • D Shift to neutral and coast
Correct answer: A
Hard braking after a blowout can cause loss of control. Hold the wheel, release the accelerator, and let speed bleed off before braking gently.
Question 10 of 25
Skids are most often caused by:
  • A Old tires
  • B Properly working brakes
  • C Driving too fast for conditions
  • D Manual transmissions
Correct answer: C
The dominant cause of skids identified by the FMCSA is driving too fast for the road or weather. Sudden steering, hard braking, or hard acceleration usually triggers them.
Question 11 of 25
Stopping distance is made up of:
  • A Brake-lag distance only
  • B Perception distance + reaction distance + brake-lag distance + braking distance
  • C Speed times weight
  • D Reaction distance only
Correct answer: B
Total stopping distance has four parts. Air brakes add a brake-lag distance not present in hydraulic systems.
Question 12 of 25
A CDL is required to operate a single vehicle with a GVWR of:
  • A 40,000 lbs or more
  • B 10,001 lbs or more
  • C 26,001 lbs or more
  • D 20,000 lbs or more
Correct answer: C
Single vehicles at or above 26,001 lbs GVWR (Class B) require a CDL. Class A applies to combinations at or above 26,001 lbs GCWR with a trailer over 10,000 lbs.
Question 13 of 25
When approaching a curve, you should:
  • A Slow down before entering and accelerate gently through it
  • B Downshift in the curve
  • C Brake while in the curve
  • D Stay at the same speed
Correct answer: A
Speed should already be set before the curve. Braking or downshifting in a curve can upset the vehicle's balance.
Question 14 of 25
Which is true about brake lining wear and adjustment?
  • A Slack adjusters need periodic checking; pushrod travel beyond limits is out-of-service
  • B Brake adjustment is the dispatcher's responsibility
  • C Brakes self-adjust forever
  • D Drum brakes never need adjustment
Correct answer: A
Slack adjusters can fail, and pushrod travel must be within limits. Drivers check; adjustment itself is a maintenance task for qualified personnel.
Question 15 of 25
Black ice is most likely on:
  • A Bridges and overpasses
  • B Roads in direct sunlight
  • C Gravel surfaces
  • D Concrete pavement only
Correct answer: A
Bridges and overpasses freeze first because cold air circulates above and below them. They are the most-asked test scenario for sudden ice.
Question 16 of 25
Which of the following is a valid reason to refuse a load?
  • A All of the above
  • B It would push your weight over legal limits
  • C The cargo is not properly secured or placarded
  • D It would make you exceed federal hours-of-service rules
Correct answer: A
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 17 of 25
When approaching a railroad crossing in a CMV that is not required to stop, you should:
  • A Slow down, look, listen, and be prepared to stop
  • B Always come to a full stop regardless of traffic
  • C Honk and proceed
  • D Cross at maximum speed to get over quickly
Correct answer: A
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 18 of 25
How does ABS help in an emergency stop?
  • A It increases brake pressure automatically
  • B It applies the parking brake
  • C It prevents wheel lockup so the driver can keep steering
  • D It always stops the vehicle in a shorter distance
Correct answer: C
ABS keeps the wheels rolling so steering control is preserved. It is not a shorter-distance device.
Question 19 of 25
The most important hand position on the steering wheel is:
  • A Both hands at the bottom
  • B One hand at 12
  • C 10 and 2 (or 9 and 3)
  • D 12 and 6
Correct answer: C
A balanced grip at 10-and-2 or 9-and-3 gives the most control. One-handed and bottom-of-wheel positions reduce reaction time.
Question 20 of 25
A controlled braking technique means:
  • A Coasting in neutral
  • B Pumping the brakes hard and fast
  • C Locking the wheels
  • 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
What does it mean when a road sign says "Bridge formation may freeze before road"?
  • A The pavement under the bridge is reinforced
  • B Bridge surfaces freeze first because of air circulation underneath
  • C Bridges are inspected only in winter
  • D The bridge is closed in winter
Correct answer: B
Cold air around bridges and overpasses cools the deck more quickly than the surrounding road, which is why ice often appears there first.
Question 22 of 25
When should you use four-way flashers?
  • A Whenever you feel like it
  • B When you are stopped or moving slowly enough to be a hazard
  • C Only at night
  • D Only on the highway
Correct answer: B
Four-ways are for vehicles stopped on or near the road or moving so slowly that they are a hazard.
Question 23 of 25
A driver should test the parking brake by:
  • A Setting the parking brake, releasing the service brakes, and gently trying to move the vehicle in low gear
  • B Pumping the brakes
  • C Driving over a speed bump
  • D Releasing the parking brake on a flat surface and tugging gently against it
Correct answer: A
The standard test: set parking brakes, gently apply throttle in low gear; if the vehicle moves, the parking brake is not holding.
Question 24 of 25
The proper following distance for a 60-foot truck traveling under 40 mph is at least:
  • A 6 seconds
  • B 10 seconds
  • C 4 seconds
  • D 1 second
Correct answer: A
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 25 of 25
A driver may keep moving when:
  • A Required emergency equipment is missing
  • B A passenger door is open
  • C A trailer brake light is out
  • D A vehicle is in safe operating condition
Correct answer: D
Federal rules forbid driving any CMV that is not in safe operating condition. Continue only after the defect is fixed.

Study tips for the Oklahoma General Knowledge exam

The General Knowledge portion of the Oklahoma CDL exam is graded out of the bank of questions the Oklahoma Department of Public Safety draws from each year. While the exact bank is not published, every question is sourced from the General Knowledge chapter of the Oklahoma 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 Oklahoma 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 Oklahoma Department of Public Safety 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 Oklahoma 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 Oklahoma 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 Oklahoma Department of Public Safety office.

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

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