Mississippi General Knowledge practice test
50 questions · 80% to pass · Required for every CDL applicant.
How to use this practice test
Read each question, click an answer, and the correct choice is highlighted with a short explanation referencing the underlying CDL Manual concept. Your live score appears at the top of the page. Refresh to reset.
This test runs entirely in your browser. Nothing is uploaded; no account is required. Pages refresh to a new randomized cut from the bank.
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1. You should NOT drive when taking which of these?
Explanation. Drowsiness-causing medications, even legal ones, can disqualify you from driving.
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2. When taking the CDL knowledge exam, when checking your vehicle, the engine should be off and the wheels chocked because:
Explanation. Chocking wheels and shutting down the engine prevents the vehicle from rolling away while you are underneath or alongside it. (Reinforcement variant — same underlying CDL Manual concept.)
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3. When taking the CDL knowledge exam, when checking lights during the pre-trip, you should turn the key on and:
Explanation. Have someone else watch, or turn lights on and off and walk around to verify each lamp is working. (Reinforcement variant — same underlying CDL Manual concept.)
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4. Convex (curved) mirrors:
Explanation. Convex mirrors widen the view but make objects appear smaller and farther away than they actually are.
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5. Carbon monoxide poisoning may be a hazard if:
Explanation. A cracked exhaust manifold or rusted-through pipe can leak CO into the cab, causing drowsiness or death.
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6. In real-world commercial driving, when making a right turn in a large vehicle, you should:
Explanation. Stay in the right lane and watch the trailer; swinging left first invites a same-direction driver to squeeze in on your right. (Reinforcement variant — same underlying CDL Manual concept.)
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7. When approaching a railroad crossing, you should:
Explanation. Always slow, look, listen, and prepare to stop. A full stop is required only for buses, hazmat, and certain placarded vehicles.
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8. You should signal continuously when turning because:
Explanation. Continuous signaling keeps other drivers informed and prevents the signal from cancelling before the turn is complete.
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9. Most state DMV CDL handbooks state that you should signal continuously when turning because:
Explanation. Continuous signaling keeps other drivers informed and prevents the signal from cancelling before the turn is complete. (Reinforcement variant — same underlying CDL Manual concept.)
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10. In real-world commercial driving, you should signal continuously when turning because:
Explanation. Continuous signaling keeps other drivers informed and prevents the signal from cancelling before the turn is complete. (Reinforcement variant — same underlying CDL Manual concept.)
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11. Per federal regulations, the 14-hour rule means a driver may not drive after the:
Explanation. After 14 consecutive hours on duty following 10 hours off, no further driving is allowed even if some of those 14 hours were not driving. (Reinforcement variant — same underlying CDL Manual concept.)
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12. Experienced commercial drivers know that which is the best way to handle a tire failure?
Explanation. Hard braking after a tire failure can cause loss of control. Hold the wheel firmly, ease off the throttle, and brake gently after slowing. (Reinforcement variant — same underlying CDL Manual concept.)
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13. Per federal regulations, you should warm up the engine before driving because:
Explanation. Allowing the engine to warm circulates oil and reduces wear before load is applied. (Reinforcement variant — same underlying CDL Manual concept.)
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14. The eye-lead time recommended for highway driving is at least:
Explanation. Look 12-15 seconds ahead so you can identify hazards in time to react smoothly.
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15. When operating a CMV in interstate commerce, most pre-trip inspections begin with which step?
Explanation. The CDL Manual lists "review last inspection report" as the first step in the seven-step pre-trip inspection. (Reinforcement variant — same underlying CDL Manual concept.)
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16. A driver placing reflective triangles after a breakdown on a divided highway should place them at:
Explanation. On a one-way or divided road, place triangles at 10, 100, and 200 feet toward approaching traffic.
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17. During a pre-trip inspection, communicating presence with the horn is appropriate when:
Explanation. Use the horn only to warn others of your presence when there is a real risk they have not seen you. (Reinforcement variant — same underlying CDL Manual concept.)
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18. During a pre-trip inspection, when driving in the mountains, gravity will:
Explanation. Going downhill, gravity adds to your speed and the distance needed to stop. (Reinforcement variant — same underlying CDL Manual concept.)
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19. You should signal a lane change for at least:
Explanation. Signal early and continuously enough for surrounding traffic to see your intent.
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20. When operating a CMV in interstate commerce, a vehicle is most likely to roll over when:
Explanation. High center of gravity plus sudden steering or braking is the recipe for rollovers. (Reinforcement variant — same underlying CDL Manual concept.)
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21. During a pre-trip inspection, a retarder helps the driver by:
Explanation. Retarders slow the vehicle without using service brakes, reducing brake wear and overheating risk. (Reinforcement variant — same underlying CDL Manual concept.)
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22. Experienced commercial drivers know that you should check your mirrors:
Explanation. Frequent mirror checks (every 5-8 seconds) are part of safe scanning. (Reinforcement variant — same underlying CDL Manual concept.)
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23. Most state DMV CDL handbooks state that aggressive driving by other motorists is best handled by:
Explanation. The safest response is to disengage and report when safe; never engage an aggressive driver. (Reinforcement variant — same underlying CDL Manual concept.)
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24. Experienced commercial drivers know that a driver placing reflective triangles after a breakdown on a divided highway should place them at:
Explanation. On a one-way or divided road, place triangles at 10, 100, and 200 feet toward approaching traffic. (Reinforcement variant — same underlying CDL Manual concept.)
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25. Per federal regulations, you should signal a lane change for at least:
Explanation. Signal early and continuously enough for surrounding traffic to see your intent. (Reinforcement variant — same underlying CDL Manual concept.)
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26. According to the FMCSA CDL Manual, the best way to recover from a drive-wheel skid is to:
Explanation. Releasing the accelerator and disengaging the clutch removes power from the drive wheels so they can regain traction. (Reinforcement variant — same underlying CDL Manual concept.)
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27. Retarders should usually be turned off when:
Explanation. On slick surfaces a retarder can cause drive wheels to skid; turn it off in those conditions.
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28. In real-world commercial driving, you should NOT drive when taking which of these?
Explanation. Drowsiness-causing medications, even legal ones, can disqualify you from driving. (Reinforcement variant — same underlying CDL Manual concept.)
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29. What does the term "perception distance" mean?
Explanation. Perception distance is the distance traveled while your brain identifies a hazard, typically about 1.5 seconds at highway speed.
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30. When merging onto a highway, you should:
Explanation. Match traffic speed and yield; stopping is dangerous and can cause rear-end collisions.
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31. Per federal regulations, when approaching a railroad crossing, you should:
Explanation. Always slow, look, listen, and prepare to stop. A full stop is required only for buses, hazmat, and certain placarded vehicles. (Reinforcement variant — same underlying CDL Manual concept.)
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32. Most state DMV CDL handbooks state that when backing a commercial vehicle, you should:
Explanation. Backing toward the driver side gives the driver a direct line of sight, which is much safer than blind-side backing. (Reinforcement variant — same underlying CDL Manual concept.)
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33. When taking the CDL knowledge exam, a driver who is convicted of DUI in any vehicle while holding a CDL faces:
Explanation. A first DUI conviction in any vehicle disqualifies a CDL for at least one year. (Reinforcement variant — same underlying CDL Manual concept.)
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34. When taking the CDL knowledge exam, controlled braking means:
Explanation. Controlled braking is firm pressure that does not lock the wheels, allowing you to continue steering. (Reinforcement variant — same underlying CDL Manual concept.)
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35. When operating a CMV in interstate commerce, retarders should usually be turned off when:
Explanation. On slick surfaces a retarder can cause drive wheels to skid; turn it off in those conditions. (Reinforcement variant — same underlying CDL Manual concept.)
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36. According to the FMCSA CDL Manual, drivers must complete a written post-trip inspection report when:
Explanation. Federal rules require a report whenever defects are found, and many carriers require one for every trip. (Reinforcement variant — same underlying CDL Manual concept.)
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37. Most state DMV CDL handbooks state that which of these is NOT a sign of a tired driver?
Explanation. A "second wind" is a brief, deceptive boost. All of the others, including the second wind, are warning signs of fatigue. (Reinforcement variant — same underlying CDL Manual concept.)
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38. When driving in fog, you should:
Explanation. High beams reflect off fog and reduce vision; low beams and slower speed are correct.
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39. During a pre-trip inspection, stab braking is used:
Explanation. Stab braking is an emergency technique for non-ABS vehicles: brake hard until wheels lock, release, brake again. (Reinforcement variant — same underlying CDL Manual concept.)
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40. When checking lights during the pre-trip, you should turn the key on and:
Explanation. Have someone else watch, or turn lights on and off and walk around to verify each lamp is working.
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41. Total stopping distance equals:
Explanation. Total stopping distance is perception + reaction + braking distance combined.
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42. When driving down a long, steep grade, you should:
Explanation. Always select a low gear before descending so engine compression helps hold speed and brakes do not overheat.
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43. In real-world commercial driving, convex (curved) mirrors:
Explanation. Convex mirrors widen the view but make objects appear smaller and farther away than they actually are. (Reinforcement variant — same underlying CDL Manual concept.)
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44. You must use low beams within how many feet of an oncoming vehicle?
Explanation. Switch to low beams within 500 feet of an oncoming vehicle to avoid blinding the other driver.
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45. When taking the CDL knowledge exam, carbon monoxide poisoning may be a hazard if:
Explanation. A cracked exhaust manifold or rusted-through pipe can leak CO into the cab, causing drowsiness or death. (Reinforcement variant — same underlying CDL Manual concept.)
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46. Experienced commercial drivers know that what is the standard color of a placard for a Class 2 (gases) hazardous material?
Explanation. Class 2 placards are red for flammable gas, green for non-flammable, and yellow/white for poison/oxygen subdivisions. (Reinforcement variant — same underlying CDL Manual concept.)
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47. Experienced commercial drivers know that when driving in the mountains, gravity will:
Explanation. Going downhill, gravity adds to your speed and the distance needed to stop. (Reinforcement variant — same underlying CDL Manual concept.)
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48. In real-world commercial driving, the 14-hour rule means a driver may not drive after the:
Explanation. After 14 consecutive hours on duty following 10 hours off, no further driving is allowed even if some of those 14 hours were not driving. (Reinforcement variant — same underlying CDL Manual concept.)
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49. Experienced commercial drivers know that a vehicle is most likely to roll over when:
Explanation. High center of gravity plus sudden steering or braking is the recipe for rollovers. (Reinforcement variant — same underlying CDL Manual concept.)
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50. When taking the CDL knowledge exam, what does the term "perception distance" mean?
Explanation. Perception distance is the distance traveled while your brain identifies a hazard, typically about 1.5 seconds at highway speed. (Reinforcement variant — same underlying CDL Manual concept.)
About the General Knowledge exam
The General Knowledge exam is required for every Class A, B, and C CDL applicant. It covers vehicle inspection, basic control, shifting, backing, communicating with other drivers, distracted driving, fatigue, hazard perception, emergency maneuvers, skid control, accident procedures, hazardous materials awareness, and federal hours-of-service rules.
This Mississippi-specific edition uses the same federal source material every U.S. state adopts. The Mississippi DPS administers the actual exam at its service centers. Bring your CDL handbook for any last-minute reference; it’s free at every Mississippi DPS office.
Once you’re consistently scoring above 90% on this practice set, you’re well above the 80% required to pass the official Mississippi exam. Drill the questions you miss most often, then take the test cold once a day for a week leading up to your appointment.
Tips that actually work
- Read every answer choice before clicking. CDL questions are famous for "best answer" wording where two choices look right.
- Don’t memorize question text — learn the underlying rule. The DMV reshuffles wording constantly.
- Keep a list of the questions you miss. Re-drill them in isolation until you can’t miss them.
- Practice in short, frequent sessions. Two 20-minute sessions per day beats one two-hour cram.
What happens after I pass?
Passing the knowledge test earns you a Commercial Learner’s Permit (CLP). You must hold the CLP for at least 14 days before you can take the road skills test, and you must drive with a CDL-holding instructor in the cab during that period. Once you pass the road skills test, your CDL is issued.