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Full CDL practice questions

Practice selected CDL topics. Some technical material uses older sources. Check current Michigan requirements before test day. Coverage and source limits

Michigan CDL Full practice questions

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Question 1 of 130
  1. 1. For federally regulated interstate CMV operation: A repaired freight truck is ready for collection. Who must still be satisfied that it is safe before driving?
  2. 2. For federally regulated interstate CMV operation: The last required report lists a defect repaired on the truck you will drive. What does signing the reviewed report acknowledge?
  3. 3. For federally regulated interstate CMV operation: A carrier wants to keep its required driver-inspection reports digitally. Which statement is correct?
  4. 4. For federally regulated interstate CMV operation: Before accepting intermodal equipment, what does the driver's specified service-brake inspection involve?
  5. 5. For federally regulated interstate CMV operation: A truck tire has a cut exposing its belt material, although its tread is deep. What is permitted?
  6. 6. For federally regulated interstate CMV operation: On a truck's front tire, what minimum depth is required at a major tread groove, away from tie bars, humps and fillets?
  7. 7. For federally regulated interstate CMV operation: What minimum major-groove tread depth applies to an ordinary freight truck's rear tires, away from tie bars, humps and fillets?
  8. 8. For federally regulated interstate CMV operation: A truck's wipers have failed, but the forecast is dry. What is the driver's equipment obligation before departure?
  9. 9. For federally regulated interstate CMV operation: Before loading out, a driver's cold tire-pressure reading is below the pressure specified for the load. What should be done?
  10. 10. For federally regulated interstate CMV operation: An ordinary truck carries no hazardous materials and is not in driveaway-towaway service. Which single-extinguisher rating meets the federal minimum?
  11. 11. For federally regulated interstate CMV operation: How must a required extinguisher's Underwriters' Laboratories rating be identified?
  12. 12. For federally regulated interstate CMV operation: Which storage arrangement satisfies the location and mounting requirement for a filled truck extinguisher?
  13. 13. For federally regulated interstate CMV operation: What condition must a required extinguisher allow the driver to determine visually?
  14. 14. For federally regulated interstate CMV operation: Which set is a complete reflective-triangle equipment option for an ordinary truck?
  15. 15. For federally regulated interstate CMV operation: An ordinary diesel truck leaks fuel after stopping on a highway. What applies before lighting or placing a flame-producing warning signal?
  16. 16. For federally regulated interstate CMV operation: A truck stops on a highway shoulder because of a breakdown, not a necessary traffic stop. What signal action is required immediately?
  17. 17. For federally regulated interstate CMV operation: A truck breaks down on a rural highway shoulder where the general warning-device rule applies. When must the devices be placed?
  18. 18. For federally regulated interstate CMV operation: Where warning triangles are required after a truck breakdown, how do the flashers affect that requirement?
  19. 19. For federally regulated interstate CMV operation: A truck is disabled on a straight divided-highway shoulder with clear sight distance. Where do the two farther warning devices belong?
  20. 20. For federally regulated interstate CMV operation: A truck is stopped within 500 feet of a hillcrest that hides it from approaching traffic. Where should the warning signal toward that obstruction go?
  21. 21. For federally regulated interstate CMV operation: A truck stops in a municipality's business district when lighted lamps are not required. What does the warning-device placement exception provide?
  22. 22. For federally regulated interstate CMV operation: A truck begins a trip with accessible, unsealed cargo that can be inspected. When is the first in-trip cargo and securement check required?
  23. 23. For federally regulated interstate CMV operation: After the first inspection of accessible cargo, which events require reexamination during the trip?
  24. 24. For federally regulated interstate CMV operation: A truck's load is sealed and the driver has been ordered not to open it for inspection. Which duty is excepted?
  25. 25. For federally regulated interstate CMV operation: A box is strapped securely inside an ordinary truck cab but blocks the driver's ready exit. What must change?
  26. 26. For federally regulated interstate CMV operation: The freight is restrained, but the truck's spare tire and tarpaulin are unsecured. What is required?
  27. 27. For federally regulated interstate CMV operation: Under the general tiedown-count rule, a seven-foot article is not blocked against forward movement. No special-purpose exception applies. What minimum number is required?
  28. 28. For federally regulated interstate CMV operation: An ordinary eight-foot article is properly blocked against forward movement. No special-purpose exception applies. Under the general count rule, how many tiedowns are required at minimum?
  29. 29. For federally regulated interstate CMV operation: A secured package blocks the right-side view from an ordinary truck's driving position. Does securement make its location acceptable?
  30. 30. For federally regulated interstate CMV operation: A toolbox leaves the driver room to steer and exit but blocks ready access to required emergency accessories. Is its position acceptable?
  31. 31. For federally regulated interstate CMV operation: An ordinary freight truck is outside the stop-required categories of 392.10. How must it approach a railroad grade crossing?
  32. 32. For federally regulated interstate CMV operation: A freight truck outside the 392.10 categories has slowed at a grade crossing. What is necessary before driving over it?
  33. 33. For federally regulated interstate CMV operation: Supplies in a truck cab restrict the driver's leg movement without blocking the windshield. Is that acceptable?
  34. 34. For federally regulated interstate CMV operation: A truck tire has no visible exposed cords, but air can be heard escaping. What does the tire rule permit?
  35. 35. For federally regulated interstate CMV operation: An ordinary freight truck has a tire loaded above its marked capacity. It has no special state permit. What is required?
  36. 36. For federally regulated interstate CMV operation: Which characteristic is required of the extinguishing agent in a truck's required extinguisher?
  37. 37. For federally regulated interstate CMV operation: A truck's horn works, but the driver believes merely having it installed fulfills the equipment rule. What does the rule also require?
  38. 38. For federally regulated interstate CMV operation: A report lists a defect on a towed unit no longer in your vehicle combination. Which specific acknowledgement exception applies?
  39. 39. For federally regulated interstate CMV operation: During acceptance of intermodal equipment, which hardware is specifically included in the driver's inspection?
  40. 40. For federally regulated interstate CMV operation: A truck uses speed-restricted tires marked 55 mph under the federal provision. The posted road limit is 65 mph. Which maximum governs those tires?
  41. 41. After pumping a hydraulic brake pedal, you hold steady pressure and the pedal slowly sinks. What is the appropriate response?
  42. 42. You must back a tall truck into an unfamiliar loading area. What should the preliminary walk-through include?
  43. 43. A helper will watch the blind area while you back toward a dock. What must you agree on before the truck moves?
  44. 44. In ordinary conditions, which scanning plan follows the CDL manual’s guidance for anticipating trouble ahead?
  45. 45. A car looks small and far away in your truck’s curved mirror. How should this affect a lane-change decision?
  46. 46. A loaded truck approaches a curve with a posted advisory speed commonly used by cars. What is the safest plan?
  47. 47. Your headlights reveal less clear roadway than the distance your truck needs to stop. What adjustment is needed?
  48. 48. Under good conditions, a 40-foot commercial vehicle is traveling at 55 mph. What following interval matches the manual’s length-and-speed guideline?
  49. 49. The truck starts to hydroplane across standing water. Which response helps the tires regain contact?
  50. 50. On a near-freezing day, your truck approaches a bridge from a road that is still wet. What should you allow for?
  51. 51. You are approaching an icy stretch with the retarder switched on. What does the CDL manual recommend?
  52. 52. After a long drive on a hot day, a properly inflated tire shows a higher pressure than its cold reading. Should you bleed air to restore the cold reading?
  53. 53. Your loaded truck is about to descend a long, steep grade. When should you select the suitable low gear?
  54. 54. A traffic queue beyond a railroad crossing leaves room for the tractor but not the entire trailer. What should you do?
  55. 55. On a slippery curve, the truck keeps sliding straight despite your steering input. What is the useful response?
  56. 56. A driver is struggling to stay awake and considers taking a stimulant to finish the delivery. What is the sound safety decision?
  57. 57. A cold medicine is sold without a prescription, but its label warns of drowsiness. What should a commercial driver understand?
  58. 58. Two loads have the same weight. One stacks the heaviest freight high; the other puts it low. Which arrangement better resists rollover?
  59. 59. A load places too little weight on the truck’s steering axle. What operating problem can result?
  60. 60. You cannot open a sealed freight container at pickup. Does its seal make gross-weight and axle-weight checks unnecessary?
  61. 61. A heavy crate can slide sideways even though it cannot move toward the cab. Is the securement problem solved?
  62. 62. A flatbed has a front-end header board behind the cab. Which cargo movement is it intended to help resist?
  63. 63. An air-brake system reaches its normal upper pressure and stops pumping air into the reservoirs. Which component controls this cut-out and later cut-in?
  64. 64. Why is removing accumulated moisture from air reservoirs especially important before freezing weather?
  65. 65. Before moving an air-braked truck, you check its supply-pressure gauges. What do they tell you?
  66. 66. The low-air warning activates while the truck is moving. What is the safe response?
  67. 67. What keeps a typical spring parking brake released while the truck is being driven?
  68. 68. On a system without protection against brake compounding, what can happen if you press the service pedal while the spring brakes are already applied?
  69. 69. One circuit of a dual air-brake system loses pressure, while the other still has air. What does this mean for the trip?
  70. 70. An automatic slack adjuster is repeatedly found out of adjustment. What is the appropriate approach?
  71. 71. In a clear, safe test area, how should you check whether the applied parking brake holds the truck?
  72. 72. During a slow, controlled service-brake check, the truck pulls sharply to one side. What does that suggest?
  73. 73. Your truck’s ABS is working during a hard stop. How should you use the brake pedal?
  74. 74. Why does the stopping-distance calculation for air brakes include an extra distance after the pedal is pressed?
  75. 75. A tractor clears a curb during a slow turn, but the trailer’s rear wheels are still approaching it. What must the driver allow for?
  76. 76. A sudden steering move travels through a tractor pulling two trailers. Which trailer is especially vulnerable to the amplified whipping motion?
  77. 77. You are driving the tractor without a trailer. Should its lighter weight make you assume it will stop more quickly?
  78. 78. In your mirror, the trailer begins swinging sideways because its wheels have locked during braking. What helps restore its path?
  79. 79. A driver proposes using the trailer hand valve to hold a parked rig while leaving the cab. Why is that unsafe?
  80. 80. A trailer air line tears apart after a breakaway. Which protection is intended to keep the leak from draining all air out of the tractor?
  81. 81. One trailer air line supplies the trailer reservoirs and controls emergency braking if its pressure is lost. Which line performs these functions?
  82. 82. After coupling a spring-braked trailer, you discover that its service and supply air lines were crossed. What problem can this cause?
  83. 83. Before backing the tractor under a semitrailer, how should its front height relate to the fifth wheel?
  84. 84. A gentle coupling pull-test seems satisfactory. During the visual check, the jaws appear around the kingpin head instead of its shank. May you depart?
  85. 85. A coupled trailer’s landing feet are a few inches above the ground. What remains necessary before departure?
  86. 86. While uncoupling, why do you pause with the tractor frame still beneath the trailer after the fifth wheel has cleared?
  87. 87. You are assembling a set of two trailers with substantially different loaded weights. Which order does the manual recommend for the safest handling?
  88. 88. You are choosing a rest-area parking space for a set of doubles. Which feature deserves special consideration?
  89. 89. A set of doubles is ready for travel. How should the service and supply shut-off valves at the rear of each trailer be positioned?
  90. 90. During a properly secured air-continuity check, no air escapes when you briefly open the final trailer’s service-line valve with the service control applied. What should you do?
  91. 91. The converter dolly’s eye is resting in the front trailer’s pintle hook. What additional connection checks are still necessary?
  92. 92. A helper reaches for the pintle-hook latch while the dolly is still supporting the rear trailer. What is the concern?
  93. 93. A tank shell looks intact, but liquid is seeping around a discharge-valve connection. Is the vehicle ready to haul the load?
  94. 94. A partially filled liquid tanker has just stopped on ice. Why can the vehicle still be pushed forward?
  95. 95. Your tanker has separate compartments divided by solid bulkheads. What must you consider when deciding which compartments to fill or empty?
  96. 96. A driver says that tank baffles make abrupt lane changes safe because they control liquid movement. What is wrong with that reasoning?
  97. 97. You change from a baffled tanker to a smooth-bore tanker. What handling change should you particularly anticipate?
  98. 98. A dispatcher asks you to fill every available gallon of a cargo tank with liquid. What must determine the actual loading amount?
  99. 99. A passenger wants to leave a suitcase in the aisle beside an emergency exit because the ride is short. What should you require?
  100. 100. Before carrying passengers, you find an emergency door that does not close securely. What is the appropriate conclusion?
  101. 101. A bus passes its exterior walk-around, but a passenger seat is loose and a handhold is damaged. Is the passenger-area inspection complete?
  102. 102. A passenger has just boarded your transit bus and is still finding a secure position. When should you begin moving?
  103. 103. A disruptive adult passenger is making continued bus operation unsafe. Which response follows the manual’s safety guidance?
  104. 104. You signal to leave a bus stop, but nearby traffic has not made room. What is the safe assumption?
  105. 105. A disabled bus must be towed, and passengers can safely get off first. What is the manual’s guidance?
  106. 106. Opening a transit bus door activates a brake-door interlock. Can that device replace the parking brake when securing the bus?
  107. 107. A child is close to the front bumper below the driver’s direct view. Which school-bus mirrors are specifically intended to help check this danger zone?
  108. 108. You counted a child at the stop, but cannot account for that child after the others board. What should happen before the bus moves?
  109. 109. What should students be taught to do if they drop an item beside the bus during unloading?
  110. 110. The final school-bus stop is complete and the bus sounds empty. What check should still be made at the end of the route?
  111. 111. After stopping a school bus at a railroad crossing, how can you improve the check for an approaching train?
  112. 112. A school bus stalls on the tracks and a train is approaching. What direction should evacuated students move?
  113. 113. While children are unloading, two students inside begin arguing. What should remain your immediate focus?
  114. 114. At an approved drop-off maneuver, backing is unavoidable and no safer option exists. Should students get off before or after the bus backs?
  115. 115. A school bus is parked close to a roadside object. As the driver steers away, why must the rear overhang be watched in the mirrors?
  116. 116. Strong gusts are pushing a school bus sideways. What is the manual’s recommended response?
  117. 117. A shipment is subject to hazardous-materials shipping-paper requirements, but the shipper says the paperwork will be emailed after you leave. What should you do?
  118. 118. You leave the controls of a truck carrying a hazardous-materials shipment that requires shipping papers. Where should those papers remain?
  119. 119. The correct hazard placard is attached, but a loose tarp covers its lower half. What needs to happen before travel?
  120. 120. Hazardous-material drums cannot slide out of the trailer, but they can strike one another and damage their fittings. Is that adequate securement?
  121. 121. A hazardous-material package bears required orientation arrows. A loader wants to lay it on its side to fit another pallet. What is the correct response?
  122. 122. Before workers begin loading hazardous material into a motor vehicle, what must the driver ensure about the vehicle itself?
  123. 123. Class 3 flammable liquid is being unloaded and a person approaches the transfer area with a lighted cigarette. What is the necessary safety response?
  124. 124. You stop to fuel the power unit of a truck carrying placarded hazardous material. Which arrangement is correct?
  125. 125. A placarded load can use a practical, permitted route around a crowded downtown area. What does the manual's safety guidance advise if going downtown would only be more convenient?
  126. 126. At pickup, you notice liquid escaping from a hazardous-material package. The shipper offers to place it on an absorbent pad. What is the proper decision?
  127. 127. Emergency responders need to identify a load’s hazards quickly. Which shipping-paper information is especially useful for finding the relevant Emergency Response Guidebook entry?
  128. 128. An unknown substance appears to be leaking from hazardous-material cargo. Should you approach and smell it to identify the chemical?
  129. 129. You suspect a hazardous-material cargo fire and the closed trailer doors are hot. What is the appropriate action?
  130. 130. Hazardous material is leaking from your stopped vehicle. A truck stop with a telephone is several miles away. Should you continue there to get help?
Review all 130 questions with answers

  1. For federally regulated interstate CMV operation: A repaired freight truck is ready for collection. Who must still be satisfied that it is safe before driving?

    Correct answer: The driver taking the truck

    The driver's own pre-driving duty remains even after repairs.

    Source: 49 CFR 396.13(a); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  2. For federally regulated interstate CMV operation: The last required report lists a defect repaired on the truck you will drive. What does signing the reviewed report acknowledge?

    Correct answer: Report review and certification of the required repair

    The signature acknowledges review and repair certification, not that the driver performed the repair.

    Source: 49 CFR 396.13(b)–(c); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  3. For federally regulated interstate CMV operation: A carrier wants to keep its required driver-inspection reports digitally. Which statement is correct?

    Correct answer: Electronic reports are allowed under the applicable recordkeeping rule

    Section 396.13(d) permits electronic creation and maintenance in accordance with 390.32; this does not waive that rule's requirements.

    Source: 49 CFR 396.13(d); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  4. For federally regulated interstate CMV operation: Before accepting intermodal equipment, what does the driver's specified service-brake inspection involve?

    Correct answer: Thoroughly inspect visible components without going underneath

    The rule describes as thorough a visual inspection as possible without physically going under the vehicle, including trailer brake connections.

    Source: 49 CFR 392.7(b), service-brake components; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  5. For federally regulated interstate CMV operation: A truck tire has a cut exposing its belt material, although its tread is deep. What is permitted?

    Correct answer: Do not operate the truck on that tire

    Exposed ply or belt material is itself a prohibited condition; adequate tread or pressure does not cure it.

    Source: 49 CFR 393.75(a)(1),(4); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  6. For federally regulated interstate CMV operation: On a truck's front tire, what minimum depth is required at a major tread groove, away from tie bars, humps and fillets?

    Correct answer: 4/32 inch

    The front wheels of trucks, truck tractors and buses have a 4/32-inch minimum measured at the specified groove locations.

    Source: 49 CFR 393.75(b); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  7. For federally regulated interstate CMV operation: What minimum major-groove tread depth applies to an ordinary freight truck's rear tires, away from tie bars, humps and fillets?

    Correct answer: 2/32 inch

    For these non-front tire positions the federal minimum is 2/32 inch.

    Source: 49 CFR 393.75(c); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  8. For federally regulated interstate CMV operation: A truck's wipers have failed, but the forecast is dry. What is the driver's equipment obligation before departure?

    Correct answer: Ensure the wipers are in working order

    Windshield wipers are among the equipment that must be in good working order; the forecast does not remove that duty.

    Source: 49 CFR 392.7(a), windshield wipers; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  9. For federally regulated interstate CMV operation: Before loading out, a driver's cold tire-pressure reading is below the pressure specified for the load. What should be done?

    Correct answer: Correct the underinflation before operation

    A vehicle may not operate on a tire whose cold pressure is below that specified for the carried load.

    Source: 49 CFR 393.75(i)(1); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  10. For federally regulated interstate CMV operation: An ordinary truck carries no hazardous materials and is not in driveaway-towaway service. Which single-extinguisher rating meets the federal minimum?

    Correct answer: 5 B:C

    For this scenario, one extinguisher rated at least 5 B:C is an option. Two rated at least 4 B:C each are the alternative.

    Source: 49 CFR 393.95 introductory scope; (a)(1)(ii),(a)(6); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  11. For federally regulated interstate CMV operation: How must a required extinguisher's Underwriters' Laboratories rating be identified?

    Correct answer: By its manufacturer's label or marking

    The extinguisher must carry the manufacturer's rating label or marking.

    Source: 49 CFR 393.95(a)(2); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  12. For federally regulated interstate CMV operation: Which storage arrangement satisfies the location and mounting requirement for a filled truck extinguisher?

    Correct answer: Accessible for use and secured against movement

    Both ready access and secure mounting are required; satisfying one does not excuse the other.

    Source: 49 CFR 393.95(a)(4); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  13. For federally regulated interstate CMV operation: What condition must a required extinguisher allow the driver to determine visually?

    Correct answer: Whether the extinguisher is fully charged

    Its design, construction and maintenance must permit visual determination of charged condition.

    Source: 49 CFR 393.95(a)(3); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  14. For federally regulated interstate CMV operation: Which set is a complete reflective-triangle equipment option for an ordinary truck?

    Correct answer: Three compliant bidirectional reflective triangles

    The listed option is three triangles meeting FMVSS 125. Other warning items may supplement, not replace, required devices.

    Source: 49 CFR 393.95(f)(1),(3); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  15. For federally regulated interstate CMV operation: An ordinary diesel truck leaks fuel after stopping on a highway. What applies before lighting or placing a flame-producing warning signal?

    Correct answer: Keep it far enough from the leak to prevent ignition

    A flame signal must not be lighted or placed where leaking flammable material could cause fire or explosion. This is not advice to choose a flame over a suitable non-flame device.

    Source: 49 CFR 392.22(b)(2)(vi); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  16. For federally regulated interstate CMV operation: A truck stops on a highway shoulder because of a breakdown, not a necessary traffic stop. What signal action is required immediately?

    Correct answer: Activate the truck's hazard warning flashers

    Hazard flashers provide the immediate warning; required device placement is a separate duty.

    Source: 49 CFR 392.22(a); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  17. For federally regulated interstate CMV operation: A truck breaks down on a rural highway shoulder where the general warning-device rule applies. When must the devices be placed?

    Correct answer: As soon as possible, within ten minutes

    Ten minutes is the outside deadline, not permission to wait when earlier placement is possible.

    Source: 49 CFR 392.22(b)(1); no special exception; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  18. For federally regulated interstate CMV operation: Where warning triangles are required after a truck breakdown, how do the flashers affect that requirement?

    Correct answer: They supplement rather than replace the required triangles

    The regulation expressly permits flashers in addition to, not instead of, required warning devices.

    Source: 49 CFR 392.22(a), final sentence; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  19. For federally regulated interstate CMV operation: A truck is disabled on a straight divided-highway shoulder with clear sight distance. Where do the two farther warning devices belong?

    Correct answer: 100 and 200 feet toward approaching traffic

    On divided or one-way roads, the farther devices warn approaching traffic at 100 and 200 feet. The third is on the traffic side within ten feet of the rear.

    Source: 49 CFR 392.22(b)(2)(v); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  20. For federally regulated interstate CMV operation: A truck is stopped within 500 feet of a hillcrest that hides it from approaching traffic. Where should the warning signal toward that obstruction go?

    Correct answer: 100–500 feet away, positioned to give ample warning

    The special obstruction rule requires a position between 100 and 500 feet that gives other highway users ample warning.

    Source: 49 CFR 392.22(b)(2)(iv); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  21. For federally regulated interstate CMV operation: A truck stops in a municipality's business district when lighted lamps are not required. What does the warning-device placement exception provide?

    Correct answer: Placement is not required by that provision

    The municipal business/residential exception applies to placement in this situation; it does not erase other applicable duties, including the flasher rule.

    Source: 49 CFR 392.22(b)(2)(iii), distinguished from (a); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  22. For federally regulated interstate CMV operation: A truck begins a trip with accessible, unsealed cargo that can be inspected. When is the first in-trip cargo and securement check required?

    Correct answer: Within the first fifty miles

    The initial in-trip check must be within fifty miles, with any necessary adjustments to prevent cargo movement or loss.

    Source: 49 CFR 392.9(b)(2),(4); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  23. For federally regulated interstate CMV operation: After the first inspection of accessible cargo, which events require reexamination during the trip?

    Correct answer: Duty change, three driving hours, or 150 miles—whichever comes first

    Each listed event independently triggers reexamination; necessary adjustments must also be made.

    Source: 49 CFR 392.9(b)(3)(i)–(iii),(4); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  24. For federally regulated interstate CMV operation: A truck's load is sealed and the driver has been ordered not to open it for inspection. Which duty is excepted?

    Correct answer: The paragraph (b) cargo-inspection duties

    The sealed-load exception concerns paragraph (b), not the general securement and unobstructed-cab requirements of paragraph (a).

    Source: 49 CFR 392.9(a),(b)(4); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  25. For federally regulated interstate CMV operation: A box is strapped securely inside an ordinary truck cab but blocks the driver's ready exit. What must change?

    Correct answer: Move it so the driver's exit remains unobstructed

    An object must not prevent free and ready exit from the cab, even if secured and outside the driver's forward view.

    Source: 49 CFR 392.9(a)(3); ordinary truck; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  26. For federally regulated interstate CMV operation: The freight is restrained, but the truck's spare tire and tarpaulin are unsecured. What is required?

    Correct answer: Secure those operating items as well as the freight

    The rule expressly includes spare tires, tarpaulins and other operating equipment, not just transported freight.

    Source: 49 CFR 392.9(a)(2); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  27. For federally regulated interstate CMV operation: Under the general tiedown-count rule, a seven-foot article is not blocked against forward movement. No special-purpose exception applies. What minimum number is required?

    Correct answer: Two tiedowns

    For an unblocked article longer than five feet but no longer than ten feet, the minimum is two regardless of weight. Other securement requirements still apply.

    Source: 49 CFR 393.110(a),(b)(2)(ii),(d); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  28. For federally regulated interstate CMV operation: An ordinary eight-foot article is properly blocked against forward movement. No special-purpose exception applies. Under the general count rule, how many tiedowns are required at minimum?

    Correct answer: One tiedown

    Proper forward blocking invokes at least one tiedown per ten feet or fraction. This count does not waive strength or other securement requirements.

    Source: 49 CFR 393.110(a),(c),(d); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  29. For federally regulated interstate CMV operation: A secured package blocks the right-side view from an ordinary truck's driving position. Does securement make its location acceptable?

    Correct answer: No; the required side view must remain clear

    Securement and required visibility are separate conditions. The self-steer-dolly exception is not involved.

    Source: 49 CFR 392.9(a)(3); ordinary truck not self-steer dolly; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  30. For federally regulated interstate CMV operation: A toolbox leaves the driver room to steer and exit but blocks ready access to required emergency accessories. Is its position acceptable?

    Correct answer: No; required emergency accessories must stay accessible

    Objects must not prevent free and ready access to required emergency accessories, independently of movement and exit clearance.

    Source: 49 CFR 392.9(a)(3); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  31. For federally regulated interstate CMV operation: An ordinary freight truck is outside the stop-required categories of 392.10. How must it approach a railroad grade crossing?

    Correct answer: At a speed that allows stopping before the nearest rail

    Even other CMVs must approach at a speed permitting a stop before the nearest rail.

    Source: 49 CFR 392.11, full section; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  32. For federally regulated interstate CMV operation: A freight truck outside the 392.10 categories has slowed at a grade crossing. What is necessary before driving over it?

    Correct answer: Use due caution to establish that the course is clear

    Slowing is not the entire duty: the driver must ascertain that the course is clear using due caution.

    Source: 49 CFR 392.11, full section; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  33. For federally regulated interstate CMV operation: Supplies in a truck cab restrict the driver's leg movement without blocking the windshield. Is that acceptable?

    Correct answer: No; the driver's legs must move freely

    The cargo rule separately protects free movement of the driver's arms and legs.

    Source: 49 CFR 392.9(a)(3); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  34. For federally regulated interstate CMV operation: A truck tire has no visible exposed cords, but air can be heard escaping. What does the tire rule permit?

    Correct answer: Do not operate the vehicle on that tire

    A flat tire or an audible leak is prohibited independently of exposed material or tread depth.

    Source: 49 CFR 393.75(a)(3); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  35. For federally regulated interstate CMV operation: An ordinary freight truck has a tire loaded above its marked capacity. It has no special state permit. What is required?

    Correct answer: Correct the overload before operating the truck

    The loading exception requires both a special state permit and the specified reduced-speed conditions. Lower speed alone does not authorize the overload.

    Source: 49 CFR 393.75(g)(1)–(2); not manufactured-home transport; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  36. For federally regulated interstate CMV operation: Which characteristic is required of the extinguishing agent in a truck's required extinguisher?

    Correct answer: It does not need protection from freezing

    The agent must not need protection from freezing; applicable toxicity requirements also remain.

    Source: 49 CFR 393.95(a)(5); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  37. For federally regulated interstate CMV operation: A truck's horn works, but the driver believes merely having it installed fulfills the equipment rule. What does the rule also require?

    Correct answer: Use the listed equipment when and as needed

    Section 392.7 covers both working condition and use of the listed equipment when needed.

    Source: 49 CFR 392.7(a), opening language and horn entry; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  38. For federally regulated interstate CMV operation: A report lists a defect on a towed unit no longer in your vehicle combination. Which specific acknowledgement exception applies?

    Correct answer: The signature is not required for that detached unit's listed defects

    Section 396.13(c) limits this signature exception to listed defects on a towed unit no longer in the combination.

    Source: 49 CFR 396.13(c), final sentence; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  39. For federally regulated interstate CMV operation: During acceptance of intermodal equipment, which hardware is specifically included in the driver's inspection?

    Correct answer: Locking pins, clevises, clamps or hooks

    The intermodal list includes the locking hardware; administrative cargo identifiers do not replace that equipment check.

    Source: 49 CFR 392.7(b), locking hardware entry; federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  40. For federally regulated interstate CMV operation: A truck uses speed-restricted tires marked 55 mph under the federal provision. The posted road limit is 65 mph. Which maximum governs those tires?

    Correct answer: 55 mph

    The vehicle may not exceed the rated limit of tires labeled for a maximum of 55 mph or less under FMVSS 119 S6.5(e). A higher road limit does not override it.

    Source: 49 CFR 393.75(f); federal text reviewed September 12, 2026; federally regulated interstate scope ↗

  41. After pumping a hydraulic brake pedal, you hold steady pressure and the pedal slowly sinks. What is the appropriate response?

    Correct answer: Have the possible hydraulic leak or other brake problem corrected before driving.

    The manual describes holding the pedal after pumping it as a hydraulic leak check. A moving pedal during the hold indicates a problem that must be corrected.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.1.5 Seven-step Inspection Method, Step 7 - Test for Hydraulic Leaks; printed page 2-7, physical PDF page 29. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  42. You must back a tall truck into an unfamiliar loading area. What should the preliminary walk-through include?

    Correct answer: Ground-level obstacles, side clearance, and overhead clearance along the entire path.

    Before backing, get out and inspect the path. A clear pavement surface does not establish clearance from branches, wires, canopies, or side obstructions.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.2.4 Backing Safely - Look at Your Path; printed page 2-8, physical PDF page 30. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  43. A helper will watch the blind area while you back toward a dock. What must you agree on before the truck moves?

    Correct answer: Clear hand signals, especially the signal that means stop.

    A helper supplements the driver’s checks. Agreed signals, particularly a stop signal, prevent confusion during backing.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.2.4 Backing Safely - Use a Helper; printed page 2-8, physical PDF page 30. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  44. In ordinary conditions, which scanning plan follows the CDL manual’s guidance for anticipating trouble ahead?

    Correct answer: Look about 12 to 15 seconds ahead while also checking nearer traffic and the mirrors.

    The manual recommends a 12-to-15-second look-ahead range. It is a scanning guide, not a reason to ignore nearby hazards or mirrors.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.4.1 Seeing Ahead; printed page 2-10, physical PDF page 32. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  45. A car looks small and far away in your truck’s curved mirror. How should this affect a lane-change decision?

    Correct answer: Allow for the mirror making objects appear smaller and farther away than they are.

    Convex mirrors expand the field of view but distort apparent size and distance. Use the complete mirror-check routine and a genuinely safe gap.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.4.2 Seeing to the Sides and Rear - How to Use Mirrors; printed page 2-11, physical PDF page 33. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  46. A loaded truck approaches a curve with a posted advisory speed commonly used by cars. What is the safest plan?

    Correct answer: Reduce speed before entering; the posted curve speed may still be too fast for the truck.

    A truck’s load and center of gravity affect its safe curve speed. Slow before the curve instead of relying on a speed suitable for a passenger car.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.6.3 Speed and Curves; printed page 2-15, physical PDF page 37. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  47. Your headlights reveal less clear roadway than the distance your truck needs to stop. What adjustment is needed?

    Correct answer: Slow enough to stop within the roadway you can see is clear.

    Do not drive faster than the available sight distance permits. Darkness, hills, curves, and weather can all shorten the clear distance ahead.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.6.4 Speed and Distance Ahead; printed page 2-15, physical PDF page 37. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  48. Under good conditions, a 40-foot commercial vehicle is traveling at 55 mph. What following interval matches the manual’s length-and-speed guideline?

    Correct answer: At least five seconds.

    The manual recommends one second per 10 feet of vehicle length below 40 mph, plus one additional second above 40 mph. Forty feet at 55 mph gives five seconds; adverse conditions require more.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.7.1 Space Ahead; printed page 2-16, physical PDF page 38. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  49. The truck starts to hydroplane across standing water. Which response helps the tires regain contact?

    Correct answer: Release the accelerator and avoid braking while the tires regain road contact.

    The older technical guide advises releasing the accelerator rather than braking during hydroplaning; on a manual-transmission vehicle it also says to disengage the clutch. Let the vehicle slow and restore tire contact instead of using abrupt inputs.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.6.2 Matching Speed to the Road Surface - Hydroplaning; printed pages 2-14, 2-15, physical PDF pages 36, 37. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  50. On a near-freezing day, your truck approaches a bridge from a road that is still wet. What should you allow for?

    Correct answer: The bridge may be icy even though nearby pavement is only wet.

    Bridges can freeze before other road surfaces, and ice may not be obvious. Make smooth control inputs and reduce speed before reaching a suspect surface.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.6.2 Matching Speed to the Road Surface - Bridges; printed page 2-14, physical PDF page 36. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  51. You are approaching an icy stretch with the retarder switched on. What does the CDL manual recommend?

    Correct answer: Turn the retarder off when traction is poor.

    Retarders act through the drive wheels and can cause a skid on slippery surfaces. The manual advises turning them off in poor-traction conditions.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.3.4 Retarders; printed pages 2-9, 2-10, physical PDF pages 31, 32. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  52. After a long drive on a hot day, a properly inflated tire shows a higher pressure than its cold reading. Should you bleed air to restore the cold reading?

    Correct answer: No; normal heating raises pressure, and bleeding air can leave the tire underinflated when it cools.

    Do not let air out of hot tires simply because their pressure has risen. If a tire is excessively hot, stop safely and let it cool while addressing the cause.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.14.1 Vehicle Checks - Tires; printed page 2-29, physical PDF page 51. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  53. Your loaded truck is about to descend a long, steep grade. When should you select the suitable low gear?

    Correct answer: Before starting down the grade, while speed is under control.

    Plan the safe speed and gear before descending. Engine braking should carry much of the speed-control load; late downshifting can fail when engine speed is too high.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.16.2 Select the Right Gear Before Starting Down the Grade; printed page 2-32, physical PDF page 54. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  54. A traffic queue beyond a railroad crossing leaves room for the tractor but not the entire trailer. What should you do?

    Correct answer: Wait before the tracks until the whole combination can clear them without stopping.

    The entire vehicle must be able to get across and clear the tracks. Never enter a crossing when congestion may trap part of the combination on it.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.15.5 Crossing the Tracks; printed page 2-31, physical PDF page 53. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  55. On a slippery curve, the truck keeps sliding straight despite your steering input. What is the useful response?

    Correct answer: Reduce the demand on the front tires and slow down so they can regain traction.

    A front-wheel skid means the front tires lack traction to steer. More steering does not restore that traction; reduce the cause of the skid and slow the vehicle.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.19.3 Front-wheel Skids; printed page 2-37, physical PDF page 59. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  56. A driver is struggling to stay awake and considers taking a stimulant to finish the delivery. What is the sound safety decision?

    Correct answer: Stop safely and rest rather than use a drug to hide fatigue.

    The manual warns against masking fatigue with drugs. Rest addresses fatigue; temporary alertness tricks do not make a tired driver reliably safe.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.11.2 Driver Factors - Fatigue and Lack of Alertness, continued; printed page 2-26, physical PDF page 48. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  57. A cold medicine is sold without a prescription, but its label warns of drowsiness. What should a commercial driver understand?

    Correct answer: Nonprescription medicine can still impair safe driving.

    Legal medicines, including cold remedies, can affect alertness and safe operation. Follow warnings and appropriate medical advice rather than treating nonprescription status as proof of safety.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 2.22.2 Other Drugs; printed pages 2-41, 2-42, physical PDF pages 63, 64. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  58. Two loads have the same weight. One stacks the heaviest freight high; the other puts it low. Which arrangement better resists rollover?

    Correct answer: The arrangement with the heaviest freight kept low.

    Keeping heavy cargo low lowers the center of gravity. Weight distribution affects stability even when total vehicle weight does not change.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 3.2.3 Don't Be Top-heavy; printed page 3-2, physical PDF page 68. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  59. A load places too little weight on the truck’s steering axle. What operating problem can result?

    Correct answer: The front tires may have too little traction for safe steering.

    An underloaded front axle can make steering unsafe. Balance cargo so neither total weight nor individual axle loading creates a control problem.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 3.2.4 Balance the Weight; printed page 3-2, physical PDF page 68. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  60. You cannot open a sealed freight container at pickup. Does its seal make gross-weight and axle-weight checks unnecessary?

    Correct answer: No; the loaded gross and axle weights still need checking.

    A container seal does not measure the load or establish suitable weight distribution. The guide retains gross-weight and axle-weight checks for sealed loads. This question supplies no current numerical Iowa weight limit or permit exception.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 3.3.5 Sealed and Containerized Loads; printed page 3-3, physical PDF page 69. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  61. A heavy crate can slide sideways even though it cannot move toward the cab. Is the securement problem solved?

    Correct answer: No; the load must also be protected against other movement during transport.

    Blocking and bracing keep cargo from shifting in directions that can damage the vehicle or affect control. Preventing movement in one direction alone may be inadequate.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 3.3.1 Blocking and Bracing; printed page 3-2, physical PDF page 68. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  62. A flatbed has a front-end header board behind the cab. Which cargo movement is it intended to help resist?

    Correct answer: Cargo moving forward during a sudden stop or crash.

    A header board helps protect the cab from freight shifting forward. It does not eliminate the need for proper securement of the whole load.

    Source: Iowa DOT official older National CDL Manual, Hy-Brid Version October 2023, July 2017 technical core; 3.3.3 Header Boards; printed page 3-3, physical PDF page 69. Older technical guide only: current media326 edition equivalence and current Iowa licensing requirements are not established by this source. ↗

  63. An air-brake system reaches its normal upper pressure and stops pumping air into the reservoirs. Which component controls this cut-out and later cut-in?

    Correct answer: The air-compressor governor.

    The compressor produces compressed air, while the governor controls when the compressor pumps air into the reservoirs.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.1.1 Air Compressor and 5.1.2 Air Compressor Governor; printed 5-1, physical PDF page 75. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  64. Why is removing accumulated moisture from air reservoirs especially important before freezing weather?

    Correct answer: Water can freeze and interfere with brake operation.

    Compressed air can carry water and oil into reservoirs. The manual calls for daily draining of manually drained tanks because water can freeze and cause brake failure.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.1.4 Air Tank Drains; printed 5-1, physical PDF page 75. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  65. Before moving an air-braked truck, you check its supply-pressure gauges. What do they tell you?

    Correct answer: How much air pressure is stored in the reservoirs.

    Supply gauges show reservoir pressure. An application-pressure gauge, when fitted, serves a different purpose by showing pressure being applied to the brakes.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.1.9 Supply Pressure Gauges and 5.1.10 Application Pressure Gauge; continued on physical PDF page 77; printed 5-2–5-3, physical PDF page 76. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  66. The low-air warning activates while the truck is moving. What is the safe response?

    Correct answer: Stop safely as soon as possible and correct the cause instead of waiting for automatic spring-brake application.

    Low air means braking capability is in danger. The manual directs a prompt safe stop while you still have control; do not wait for further pressure loss.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.4.7 Low Air Pressure; printed 5-9, physical PDF page 83. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  67. What keeps a typical spring parking brake released while the truck is being driven?

    Correct answer: Air pressure holding back the powerful spring.

    Spring brakes apply mechanically when their hold-off air is removed. Air pressure holds the spring back during normal released operation.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.1.14 Spring Brakes; printed 5-3, physical PDF page 77. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  68. On a system without protection against brake compounding, what can happen if you press the service pedal while the spring brakes are already applied?

    Correct answer: Combined spring and air forces can damage the brakes.

    The manual warns that service-brake force added to applied spring-brake force can damage components. Know the controls and protective features of the vehicle you operate.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.1.15 Parking Brake Controls, compounding caution; printed 5-3, physical PDF page 77. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  69. One circuit of a dual air-brake system loses pressure, while the other still has air. What does this mean for the trip?

    Correct answer: Braking is reduced; stop safely and have the system repaired.

    A dual system separates circuits but does not make a circuit failure harmless. The remaining brakes may not stop the vehicle normally.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.2 Dual Air Brake; printed 5-5, physical PDF page 79. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  70. An automatic slack adjuster is repeatedly found out of adjustment. What is the appropriate approach?

    Correct answer: Have qualified personnel find and repair the underlying problem.

    Repeated manual adjustment can hide an underlying mechanical defect. The manual directs attention to proper repair, not recurring adjustment as a substitute.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.3.2 During Step 5 Walk-around Inspection, automatic slack adjusters; printed 5-6, physical PDF page 80. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  71. In a clear, safe test area, how should you check whether the applied parking brake holds the truck?

    Correct answer: Use a low gear and pull gently against the applied brake.

    A gentle pull in low gear checks holding ability without an aggressive movement. This knowledge item does not replace an examiner-supervised skills inspection.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.3.3 Step 7 Final Air Brake Check, Test Parking Brake; printed 5-7, physical PDF page 81. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  72. During a slow, controlled service-brake check, the truck pulls sharply to one side. What does that suggest?

    Correct answer: A possible brake problem that needs attention before normal travel.

    The manual’s low-speed service-brake check looks for pulling, unusual feel, or delayed action. An abnormal result must not be dismissed.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.3.3 Step 7 Final Air Brake Check, Test Service Brakes; printed 5-7, physical PDF page 81. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  73. Your truck’s ABS is working during a hard stop. How should you use the brake pedal?

    Correct answer: Apply the braking force needed to stop safely and remain in control.

    ABS manages impending wheel lock automatically. It helps preserve control but does not guarantee a shorter stop or excuse unsafe speed and spacing.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.4.2 Braking with Antilock Brakes; printed 5-8, physical PDF page 82. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  74. Why does the stopping-distance calculation for air brakes include an extra distance after the pedal is pressed?

    Correct answer: Air takes time to travel through the system and operate the brakes.

    Brake lag is the interval between the driver’s application and effective braking. It adds to perception, reaction, and braking distances.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 5.4.4 Stopping Distance; printed 5-8, physical PDF page 82. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  75. A tractor clears a curb during a slow turn, but the trailer’s rear wheels are still approaching it. What must the driver allow for?

    Correct answer: The rear wheels track inside the path of the front wheels.

    Offtracking makes the trailer wheels follow a shorter, inside path. Plan a safe turn that provides room for the whole vehicle without creating a squeeze hazard.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.1.6 Turn Wide; printed 6-3, physical PDF page 87. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  76. A sudden steering move travels through a tractor pulling two trailers. Which trailer is especially vulnerable to the amplified whipping motion?

    Correct answer: The last trailer.

    Rearward amplification can make the last trailer move much more severely than the tractor. Smooth, planned steering reduces this rollover hazard.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.1.2 Steer Gently and 7.1.2 Beware of the Crack-the-whip Effect; additional physical PDF page 99; printed 6-1 and 7-1, physical PDF page 85. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  77. You are driving the tractor without a trailer. Should its lighter weight make you assume it will stop more quickly?

    Correct answer: No; a bobtail tractor can have poor braking traction and need extra stopping room.

    The manual warns that bobtail tractors can be difficult to stop smoothly. Reduced load on the drive wheels can reduce available traction.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.1.3 Brake Early; printed 6-1, physical PDF page 85. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  78. In your mirror, the trailer begins swinging sideways because its wheels have locked during braking. What helps restore its path?

    Correct answer: Release the braking that locked the trailer wheels so they can regain traction.

    A trailer-wheel braking skid requires the wheels to roll again to regain traction. Extra trailer braking worsens the skid.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.1.5 Prevent Trailer Skids; continued on physical PDF page 87; printed 6-2–6-3, physical PDF page 86. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  79. A driver proposes using the trailer hand valve to hold a parked rig while leaving the cab. Why is that unsafe?

    Correct answer: Air can leak away and release those brakes; use the proper parking controls and secure the vehicle.

    The hand valve is for testing trailer brakes, not unattended parking or ordinary driving. Air-operated service brakes may release as pressure leaks away.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.2.1 Trailer Hand Valve; printed 6-4, physical PDF page 88. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  80. A trailer air line tears apart after a breakaway. Which protection is intended to keep the leak from draining all air out of the tractor?

    Correct answer: The tractor protection valve closing the air supply to the trailer.

    The tractor protection valve helps preserve air in the tractor if the trailer separates or develops a major leak.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.2.2 Tractor Protection Valve; printed 6-5, physical PDF page 89. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  81. One trailer air line supplies the trailer reservoirs and controls emergency braking if its pressure is lost. Which line performs these functions?

    Correct answer: The emergency or supply line.

    The supply line charges trailer tanks and controls emergency braking. The service line carries the braking command associated with the pedal or hand control.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.2.4 Trailer Air-lines; printed 6-5, physical PDF page 89. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  82. After coupling a spring-braked trailer, you discover that its service and supply air lines were crossed. What problem can this cause?

    Correct answer: The trailer reservoirs may not charge, so the spring brakes may not release.

    Crossed lines may send supply air into the service line instead of charging the reservoirs and releasing spring brakes. Verify correct connections and test trailer braking before driving.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.2.5 Hose Couplers (Glad Hands), crossed air-lines continuation; printed 6-6, physical PDF page 90. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  83. Before backing the tractor under a semitrailer, how should its front height relate to the fifth wheel?

    Correct answer: Low enough that the tractor raises the trailer slightly as it backs under.

    Correct height supports proper engagement. A trailer set too high can miss the locking mechanism; one set too low can be damaged.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.4.1 Coupling Tractor-Semitrailers, Step 6 Check Trailer Height; printed 6-8, physical PDF page 92. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  84. A gentle coupling pull-test seems satisfactory. During the visual check, the jaws appear around the kingpin head instead of its shank. May you depart?

    Correct answer: No; the coupling is not correct and must be fixed before travel.

    Verify that the jaws close around the kingpin shank, the fifth-wheel plates meet, and the locks are secured. A tug alone does not replace the visual check.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.4.1 Coupling Tractor-Semitrailers, Step 13 Inspect Coupling; continued on physical PDF page 93; printed 6-8–6-9, physical PDF page 92. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  85. A coupled trailer’s landing feet are a few inches above the ground. What remains necessary before departure?

    Correct answer: Raise the landing gear fully and secure its crank handle.

    Partly raised landing gear can catch on tracks or other obstructions. Fully raise it, secure the handle, and check tractor-to-trailer clearance.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.4.1 Coupling Tractor-Semitrailers, Step 15 Raise Front Trailer Supports (Landing Gear); printed 6-9, physical PDF page 93. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  86. While uncoupling, why do you pause with the tractor frame still beneath the trailer after the fifth wheel has cleared?

    Correct answer: To check that the landing gear and ground support the trailer, with the frame still available as protection if it drops.

    The partial pull-out lets you confirm support before fully clearing the trailer. Firm ground, straight alignment, and correct landing-gear placement are essential.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 6.4.2 Uncoupling Tractor-Semitrailers, Steps 7–9; continued on physical PDF page 94; printed 6-9–6-10, physical PDF page 93. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  87. You are assembling a set of two trailers with substantially different loaded weights. Which order does the manual recommend for the safest handling?

    Correct answer: The more heavily loaded trailer first, immediately behind the tractor.

    For the safest handling, place the heavier semitrailer ahead of the lighter one. Multiple-trailer combinations require attention to how the load is distributed between units.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 7.2.1 Coupling Twin Trailers, loaded-trailer order; printed 7-1, physical PDF page 99. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  88. You are choosing a rest-area parking space for a set of doubles. Which feature deserves special consideration?

    Correct answer: A route that lets the entire rig pull straight through when leaving.

    Avoid a parking position that traps a set of doubles in a difficult escape. Plan the exit before entering the space.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 7.1.7 Parking the Vehicle; printed 7-1, physical PDF page 99. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  89. A set of doubles is ready for travel. How should the service and supply shut-off valves at the rear of each trailer be positioned?

    Correct answer: Open at the first trailer and closed at the rearmost trailer.

    Air must flow through intermediate connections to the rear unit, while the final exposed outlets must be closed. Check dolly valves as applicable too.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 7.3.1 Additional Checks, Double and Triple Trailers, shut-off valves; printed 7-3, physical PDF page 101. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  90. During a properly secured air-continuity check, no air escapes when you briefly open the final trailer’s service-line valve with the service control applied. What should you do?

    Correct answer: Find and correct the lack of air flow through the trailers and dollies before travel.

    The check establishes that air reaches the rear of the complete combination. A closed intermediate valve or other problem can leave rear brakes without the required control pressure.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 7.4.1 Additional Air Brake Checks, Check That Air Flows to All Trailers; printed 7-4, physical PDF page 102. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  91. The converter dolly’s eye is resting in the front trailer’s pintle hook. What additional connection checks are still necessary?

    Correct answer: Check that the hook is latched and the safety chains are secured.

    A seated eye is not the complete connection check. Inspect the latch, chains, air connections, and electrical connections before operation.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 7.3.1 Additional Checks, converter-dolly connections; printed 7-4, physical PDF page 102. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  92. A helper reaches for the pintle-hook latch while the dolly is still supporting the rear trailer. What is the concern?

    Correct answer: The dolly tow bar can fly upward; remove the dolly from beneath the rear trailer before unhitching it.

    The manual warns not to unlock the pintle with the dolly still under the rear trailer. Follow the safe uncoupling order and secure every unit.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 7.2.2 Uncoupling Twin Trailers, Uncouple Rear Trailer and Uncouple Converter Dolly; continued on physical PDF page 101; printed 7-2–7-3, physical PDF page 100. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  93. A tank shell looks intact, but liquid is seeping around a discharge-valve connection. Is the vehicle ready to haul the load?

    Correct answer: No; valve, pipe, hose, and connection leaks are part of the tank inspection too.

    Tank inspection includes the shell, valves, pipes, hoses, covers, and vents. Do not transport a load in a leaking tank system.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 8.1.1 Leaks; printed 8-1 (printed header displays 8-8-1), physical PDF page 103. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  94. A partially filled liquid tanker has just stopped on ice. Why can the vehicle still be pushed forward?

    Correct answer: Liquid continuing to surge inside the tank can push against its end.

    Liquid in a partly filled tank can continue moving after the vehicle slows or stops. On a slick surface, that surge can move the vehicle.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 8.2.2 Danger of Surge; continued on physical PDF page 104; printed 8-1–8-2 (printed headers display 8-8-1 and 8-8-2), physical PDF page 103. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  95. Your tanker has separate compartments divided by solid bulkheads. What must you consider when deciding which compartments to fill or empty?

    Correct answer: How the resulting load distributes weight over the vehicle and its axles.

    Bulkheads divide the load into smaller tanks, but uneven filling or unloading can still overload the front or rear. Plan weight distribution throughout the operation.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 8.2.3 Bulkheads; printed 8-2 (printed header displays 8-8-2), physical PDF page 104. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  96. A driver says that tank baffles make abrupt lane changes safe because they control liquid movement. What is wrong with that reasoning?

    Correct answer: Baffles reduce forward-and-back surge, but sideways surge can still contribute to rollover.

    Openings in baffles allow flow between areas of the tank. They limit longitudinal surge, not all lateral movement or rollover risk.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 8.2.4 Baffled Tanks; printed 8-2 (printed header displays 8-8-2), physical PDF page 104. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  97. You change from a baffled tanker to a smooth-bore tanker. What handling change should you particularly anticipate?

    Correct answer: Stronger forward-and-back surge, requiring especially smooth starts and stops.

    A smooth-bore tank has no baffles to slow longitudinal liquid flow. Anticipate stops and make gradual control changes.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 8.2.5 Un-baffled Tanks and 8.3.1 Drive Smoothly; printed 8-2 (printed header displays 8-8-2), physical PDF page 104. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  98. A dispatcher asks you to fill every available gallon of a cargo tank with liquid. What must determine the actual loading amount?

    Correct answer: Required expansion space, the liquid’s weight, and applicable vehicle weight limits.

    Liquids can expand in transit, so loading must allow the appropriate outage. Dense liquids can also reach weight limits before filling the tank’s volume.

    Source: Iowa DOT official older Commercial Driver's License Manual, Hy-Brid Version October 2023 with July 2017 technical core; 8.2.6 Outage and 8.2.7 How Much to Load?; printed 8-2 (printed header displays 8-8-2), physical PDF page 104. Older technical guidance read 2026-10-01, not confirmation of the current media/326 edition, current Iowa qualification law, or current skills-test administration. ↗

  99. A passenger wants to leave a suitcase in the aisle beside an emergency exit because the ride is short. What should you require?

    Correct answer: Stow it securely without obstructing an aisle, doorway, or exit.

    Passenger baggage must not block access or become a moving hazard. A short journey does not make an obstructed escape path safe.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 4.2 Loading and Trip Start; printed 4-1–4-2, physical PDF page 71–72; reader lines 5463–5473. ↗

  100. Before carrying passengers, you find an emergency door that does not close securely. What is the appropriate conclusion?

    Correct answer: The defect must be addressed before operating the bus with passengers.

    The bus inspection includes properly operating doors, exits, and warning devices. Do not substitute an improvised restraint that defeats emergency access.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 4.1.2 Access Doors and Panels; 4.1.3 Bus Interior; printed 4-1, physical PDF page 71; reader lines 5432–5454. ↗

  101. A bus passes its exterior walk-around, but a passenger seat is loose and a handhold is damaged. Is the passenger-area inspection complete?

    Correct answer: No; passenger seats and handholds must also be safe and secure.

    Interior safety checks include seats, handholds, aisles, steps, and emergency equipment. Exterior condition alone is not enough to establish passenger safety.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 4.1.3 Bus Interior; printed 4-1, physical PDF page 71; reader lines 5437–5449. ↗

  102. A passenger has just boarded your transit bus and is still finding a secure position. When should you begin moving?

    Correct answer: After the passenger is seated or otherwise braced, then accelerate smoothly.

    Wait for boarding passengers to be seated or braced. Smooth acceleration helps prevent falls.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 4.3.2 At Stops; printed 4-3, physical PDF page 73; reader lines 5579–5585. ↗

  103. A disruptive adult passenger is making continued bus operation unsafe. Which response follows the manual’s safety guidance?

    Correct answer: Manage the problem at a safe location rather than putting the person off where it would be unsafe.

    Disruptive riders must not distract the driver into unsafe operation. The manual warns against discharging a rider where it would be unsafe.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 4.3.2 At Stops, disruptive riders; printed 4-3, physical PDF page 73; reader lines 5586–5592. ↗

  104. You signal to leave a bus stop, but nearby traffic has not made room. What is the safe assumption?

    Correct answer: The signal does not guarantee a gap; check traffic and move only when safe.

    The manual warns against assuming that signaling gives you the right of way when leaving a stop. Observe the traffic and use a safe opportunity to merge.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 4.3.3 Common Accidents; printed 4-3, physical PDF page 73; reader lines 5593–5605. ↗

  105. A disabled bus must be towed, and passengers can safely get off first. What is the manual’s guidance?

    Correct answer: Unload the passengers before towing.

    The manual advises against towing with passengers aboard unless unloading would be unsafe. In that exceptional situation, tow only to the nearest safe unloading place.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 4.5 Prohibited Practices, towing a disabled bus; printed 4-3, physical PDF page 73; reader lines 5658–5668. ↗

  106. Opening a transit bus door activates a brake-door interlock. Can that device replace the parking brake when securing the bus?

    Correct answer: No; use the proper parking brake rather than relying on the interlock.

    A brake-door interlock is not the parking brake. Follow the bus’s proper parking and securement procedure.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 4.6 Use of Brake-door Interlocks; printed 4-4, physical PDF page 74; reader lines 5671–5677. ↗

  107. A child is close to the front bumper below the driver’s direct view. Which school-bus mirrors are specifically intended to help check this danger zone?

    Correct answer: The correctly adjusted front crossover mirrors.

    Crossover mirrors show areas immediately in front of the bus and near the front wheels and service door. Use all mirrors in a systematic check; no single mirror covers every danger zone.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 10.1.5 Outside Left and Right Side Crossover Mirrors; printed 10-2, physical PDF page 128; reader lines 10044–10069. ↗

  108. You counted a child at the stop, but cannot account for that child after the others board. What should happen before the bus moves?

    Correct answer: Secure the bus, take the key, and check around and underneath it.

    The driver must account for children before departure. If a child outside cannot be located, secure the vehicle and inspect the surrounding danger zones.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 10.2.2 Loading Procedures; printed 10-4, physical PDF page 130; reader lines 10153–10175. ↗

  109. What should students be taught to do if they drop an item beside the bus during unloading?

    Correct answer: Leave it, move to a safe place, and get the driver’s attention.

    A child reaching for a dropped item may disappear from the driver’s view. The safe instruction is to leave it and notify the driver from outside the danger zone.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 10.2.5 Special Dangers of Loading and Unloading, Dropped or Forgotten Objects; printed 10-5, physical PDF page 131; reader lines 10305–10318. ↗

  110. The final school-bus stop is complete and the bus sounds empty. What check should still be made at the end of the route?

    Correct answer: Walk through and around the bus, checking especially for sleeping students and other problems.

    A physical post-trip inspection can find sleeping students, belongings, damage, and equipment problems that a quick mirror glance misses.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 10.2.6 Post-trip Inspection; printed 10-6, physical PDF page 132; reader lines 10327–10342. ↗

  111. After stopping a school bus at a railroad crossing, how can you improve the check for an approaching train?

    Correct answer: Silence passengers and noisy equipment, open the service door and driver’s window, and look and listen.

    The manual recommends reducing noise and opening the service door and driver's window to look and listen. Follow applicable state and local school-bus procedures as well; inactive warning lights do not prove the tracks are clear.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 10.4.3 Recommended Procedures, At the Crossing; printed 10-9, physical PDF page 135; reader lines 10551–10561. ↗

  112. A school bus stalls on the tracks and a train is approaching. What direction should evacuated students move?

    Correct answer: Away from the tracks and toward the approaching train, at an angle away from the bus.

    Get everyone out and clear immediately. Moving away from the tracks toward the approaching train helps avoid the likely path of debris if the train hits the bus.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 10.4.4 Special Situations, Bus Stalls or Trapped on Tracks; printed 10-9, physical PDF page 135; reader lines 10574–10579. ↗

  113. While children are unloading, two students inside begin arguing. What should remain your immediate focus?

    Correct answer: The children outside and the unloading danger zones; address the behavior once they are safe.

    Loading and unloading require the driver’s full outside attention. If needed, stop and secure the bus at a safe place to deal with a behavior problem after the unloading students are safe.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 10.5.1 Don't Deal with On-bus Problems When Loading and Unloading; 10.5.2 Handling Serious Problems; printed 10-9, physical PDF page 135; reader lines 10608–10628. ↗

  114. At an approved drop-off maneuver, backing is unavoidable and no safer option exists. Should students get off before or after the bus backs?

    Correct answer: After backing, so students are not outside the bus during the maneuver.

    Avoid backing wherever possible. If it is unavoidable, follow the lookout and inspection procedures and never back while students are outside; at a drop-off, back before unloading.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 10.7.3 Backing; printed 10-11, physical PDF page 137; reader lines 10751–10777. ↗

  115. A school bus is parked close to a roadside object. As the driver steers away, why must the rear overhang be watched in the mirrors?

    Correct answer: The tail can swing toward nearby objects on the side opposite the turn.

    A bus’s rear overhang can swing outward as it turns. Check mirrors before and during the turn to protect the clearance beside the rear of the bus.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 10.7.4 Tail Swing; printed 10-11, physical PDF page 137; reader lines 10778–10781. ↗

  116. Strong gusts are pushing a school bus sideways. What is the manual’s recommended response?

    Correct answer: Hold the wheel firmly, reduce speed, and stop safely off the roadway if necessary while coordinating with dispatch.

    The broad side of a bus can catch strong winds. Anticipate gusts, slow down, and wait safely if conditions cannot be managed.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 10.7.2 Driving in High Winds; printed 10-11, physical PDF page 137; reader lines 10738–10750. ↗

  117. A shipment is subject to hazardous-materials shipping-paper requirements, but the shipper says the paperwork will be emailed after you leave. What should you do?

    Correct answer: Do not accept it for transportation until the required, properly prepared shipping paper is available.

    This shipment requires shipping papers. Labels or a promise of later paperwork do not replace the properly prepared hazard information needed before accepting it for transportation.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.6.10 Where to Keep Shipping Papers and Emergency Response Information; printed 9-15, physical PDF page 119; reader lines 9361–9378. Retained federal corroboration, read September 29, 2026 (not re-fetched for this Iowa asset): 49 CFR 177.817(a), (d), https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-177/subpart-A/section-177.817. ↗

  118. You leave the controls of a truck carrying a hazardous-materials shipment that requires shipping papers. Where should those papers remain?

    Correct answer: In the driver-side door holder or on the driver’s seat, readily identifiable.

    Responders must be able to find the papers promptly. At the controls, keep them within reach while belted and visible or in the driver-door holder; away from the controls, use that holder or the driver’s seat.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.6.10 Where to Keep Shipping Papers and Emergency Response Information; printed 9-15, physical PDF page 119; reader lines 9361–9378. Retained federal corroboration, read September 29, 2026 (not re-fetched for this Iowa asset): 49 CFR 177.817(e), https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-177/subpart-A/section-177.817. ↗

  119. The correct hazard placard is attached, but a loose tarp covers its lower half. What needs to happen before travel?

    Correct answer: Secure the tarp and restore the placard’s required visibility and legibility.

    A placard must remain clear of obstructions such as tarps and be maintained so its message is legible. Merely having the right placard somewhere on the vehicle is insufficient.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.3.10 Placarding, continued; printed 9-8–9-9, physical PDF page 113 (also page 112); reader lines 8731–8748. Retained federal corroboration, read September 29, 2026 (not re-fetched for this Iowa asset): 49 CFR 172.516(c)(2), (6), https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-172/subpart-F/section-172.516. ↗

  120. Hazardous-material drums cannot slide out of the trailer, but they can strike one another and damage their fittings. Is that adequate securement?

    Correct answer: No; secure them against shifting, including movement between the packages.

    Secure packages against movement during normal transportation and protect valves or fittings from damage. Relative movement between packages can create leaks even inside a closed trailer.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.4.1 General Loading Requirements, Secure Against Movement; printed 9-10, physical PDF page 114; reader lines 8897–8899, 8908–8924. Retained federal corroboration, read September 29, 2026 (not re-fetched for this Iowa asset): 49 CFR 177.834(a), https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-177/subpart-B/section-177.834. ↗

  121. A hazardous-material package bears required orientation arrows. A loader wants to lay it on its side to fit another pallet. What is the correct response?

    Correct answer: Keep the package in the orientation indicated by the markings throughout transport.

    Required orientation markings describe how the package must be positioned, not merely how it should look at delivery.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.3.7 Package Markings and Labels; printed 9-8, physical PDF page 112; reader lines 8665–8693. Retained federal corroboration, read September 29, 2026 (not re-fetched for this Iowa asset): 49 CFR 177.834(b), https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-177/subpart-B/section-177.834. ↗

  122. Before workers begin loading hazardous material into a motor vehicle, what must the driver ensure about the vehicle itself?

    Correct answer: Set the parking brake securely and take other reasonable precautions against movement.

    Vehicle movement during a transfer can damage containers or connections. The securement requirement applies before loading or unloading begins.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.4.1 General Loading Requirements; printed 9-10, physical PDF page 114; reader lines 8897–8899. Retained federal corroboration, read September 29, 2026 (not re-fetched for this Iowa asset): 49 CFR 177.834(e), https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-177/subpart-B/section-177.834. ↗

  123. Class 3 flammable liquid is being unloaded and a person approaches the transfer area with a lighted cigarette. What is the necessary safety response?

    Correct answer: Keep the ignition source away and prevent smoking near the loading or unloading operation.

    Smoking and flames create an ignition hazard during flammable-liquid loading and unloading. Keep those ignition sources away from the operation.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.4.1 General Loading Requirements, No Smoking; printed 9-10, physical PDF page 114; reader lines 8911–8918. Retained federal corroboration, read September 29, 2026 (not re-fetched for this Iowa asset): 49 CFR 177.834(c), (d), https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-177/subpart-B/section-177.834. ↗

  124. You stop to fuel the power unit of a truck carrying placarded hazardous material. Which arrangement is correct?

    Correct answer: Shut off the engine and have a person control fueling at the fill point.

    For the covered vehicle, the engine must not operate during fueling, and a person must control the process at the point where the fuel tank is filled.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.6.7 Refuel with Engine Off; printed 9-14, physical PDF page 118; reader lines 9337–9340. Retained federal corroboration, read September 29, 2026 (not re-fetched for this Iowa asset): 49 CFR 397.15, https://www.ecfr.gov/current/title-49/subtitle-B/chapter-III/subchapter-B/part-397/subpart-A/section-397.15. ↗

  125. A placarded load can use a practical, permitted route around a crowded downtown area. What does the manual's safety guidance advise if going downtown would only be more convenient?

    Correct answer: Use the route around the crowded area despite the inconvenience.

    The manual advises avoiding heavily populated areas when another route is available and checking applicable permits and route restrictions before starting.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.6.5 Route Restrictions; printed 9-14, physical PDF page 118; reader lines 9291–9311. ↗

  126. At pickup, you notice liquid escaping from a hazardous-material package. The shipper offers to place it on an absorbent pad. What is the proper decision?

    Correct answer: Refuse the leaking shipment and have the problem handled safely before transport.

    The driver’s responsibilities include refusing leaking packages and improper shipments. A pad or a waiver does not repair containment.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.2.3 The Driver; printed 9-2, physical PDF page 106; reader lines 8105–8112. ↗

  127. Emergency responders need to identify a load’s hazards quickly. Which shipping-paper information is especially useful for finding the relevant Emergency Response Guidebook entry?

    Correct answer: The proper shipping name and hazardous-material identification number.

    The ERG is indexed using material identification information, including proper shipping names and identification numbers. Accurate papers help responders identify the material.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.7.1 Emergency Response Guidebook; printed 9-15, physical PDF page 119; reader lines 9414–9425. ↗

  128. An unknown substance appears to be leaking from hazardous-material cargo. Should you approach and smell it to identify the chemical?

    Correct answer: No; use shipment information from a safe position and avoid contact or inhalation.

    Do not identify a leak by touching or smelling it. Toxic material can injure you, and smell is not a reliable warning of danger.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.7.3 Fires, cargo leaks; printed 9-16, physical PDF page 120; reader lines 9464–9472. ↗

  129. You suspect a hazardous-material cargo fire and the closed trailer doors are hot. What is the appropriate action?

    Correct answer: Keep the doors closed, call for emergency help, and warn people away.

    Opening doors can feed the fire with oxygen. Hazardous-material fires require specialized training and equipment; keep shipment information available for responders.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.7.3 Fires; printed 9-16, physical PDF page 120; reader lines 9445–9463. ↗

  130. Hazardous material is leaking from your stopped vehicle. A truck stop with a telephone is several miles away. Should you continue there to get help?

    Correct answer: No; move only as safety requires, keep people away, and summon help without spreading the leak along the road.

    The manual warns against continuing a leaking journey merely to find help. Protect yourself, keep others away and upwind, and give emergency responders the shipment information.

    Source: Iowa DOT-hosted CDL Manual, Hy-Brid October 2023; section text Version July 2017 (older source, not verified as current catalog edition). 9.7.2 Crashes/Incidents; 9.7.3 Fires, leaking cargo; printed 9-15–9-16, physical PDF page 120 (also page 119); reader lines 9426–9441, 9473–9515. ↗

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Question reference: mi-cdl-general-001

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Home / Michigan / CDL

Full CDL practice questions

All 130 operating-rule and technical questions in one session, including specialist equipment topics. These are the same questions as the short sets, not additional records. Michigan licensing remains separate.

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