General Knowledge CDL Practice Test

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  1. You are driving a loaded tractor-trailer at 55 mph on a dry road. About how many seconds of following distance should you keep from the vehicle ahead?
  2. What blood alcohol concentration (BAC) while operating a commercial motor vehicle (CMV) triggers mandatory CDL disqualification under federal regulations?
  3. Which of the following is defined as a 'serious traffic violation' that can lead to CDL disqualification if committed twice within three years?
  4. Under the federal hand-held mobile telephone restriction, what is a CMV driver prohibited from doing while driving?
  5. A CMV driver is convicted of a moving traffic violation (not a parking violation) while driving their personal vehicle. Within how many days must the driver notify their employer?
  6. How much steering wheel play (measured at the rim) is considered a vehicle defect during an inspection?
  7. During a vehicle inspection, a driver finds that one-fourth or more of the leaves in a leaf spring are missing or broken. What is the correct classification of this defect?
  8. What is the minimum tire tread depth required on the steering axle of a commercial motor vehicle?
  9. Which of the following is specifically listed as a brake system defect to look for during a vehicle inspection?
  10. Which commercial vehicles were first required by the Department of Transportation to be equipped with antilock braking systems (ABS), effective for vehicles built on or after March 1, 1997?
  11. Which of the following is a true statement about how antilock braking systems (ABS) affect vehicle braking?
  12. Why should a driver turn off the vehicle's retarder when the road is wet, icy, or snow-covered?
  13. On a trailer equipped with ABS, where is the malfunction lamp typically located?
  14. When starting to accelerate a CMV on a surface with poor traction, such as rain or snow, what should a driver do?
  15. Why does the manual recommend holding the steering wheel firmly with both hands on opposite sides?
  16. What does the amount of brake pedal pressure needed to stop a CMV smoothly depend on?
  17. On a manual transmission, when is double-clutching required to change gears?
  18. Which two methods can a driver use to know when to shift up through the gears?
  19. What is the correct practice for downshifting before descending a hill or entering a curve?
  20. Which of the following is one of the six basic safety rules for backing a commercial motor vehicle?
  21. Before backing a commercial vehicle, what should a driver do first?
  22. When using a helper while backing, what should the driver and helper agree on before backing begins?
  23. How far ahead should a driver typically look while driving, according to the AAMVA manual's visual search guidance?
  24. During a lane change, at which points should a driver check mirrors, according to the manual?
  25. What is true about convex mirrors on a commercial motor vehicle, compared to flat (plane) mirrors?
  26. What are the three rules for using turn signals described in the AAMVA manual?
  27. If you must stop on a one-way or divided highway, where should you place your three warning triangles?
  28. On a two-way or undivided highway, how should the three warning triangles be placed around a stopped vehicle?
  29. If you stop near a curve or hill crest where other drivers cannot see your vehicle within 500 feet, what should you do with your warning triangles?
  30. At 55 mph, on dry pavement, in ideal conditions, what is the minimum total stopping distance for a commercial motor vehicle according to the AAMVA CDL manual?
  31. According to the CDL manual, if a driver doubles speed from 20 mph to 40 mph, how much greater does the impact and braking distance become?
  32. At what speed can hydroplaning begin to occur on a wet road, according to the CDL manual?
  33. Per the CDL manual's guidance on matching speed to the road surface, how much should a driver reduce speed on a wet road compared to normal dry-road speed?
  34. Using the CDL manual's following-distance rule, how many seconds of following distance should a driver keep behind the vehicle ahead when driving a 40-foot truck at 35 mph?
  35. A driver is operating a 60-foot rig at 50 mph. Per the CDL manual's following-distance rule, how many seconds of following distance should be maintained?
  36. Why does the CDL manual warn drivers not to simply trust posted bridge and overpass clearance heights?
  37. Why does the CDL manual instruct drivers not to swing wide to the left before starting a right turn in a large vehicle?
  38. According to the CDL manual, approximately how far ahead can a driver see at night with low-beam headlights compared to high beams?
  39. Per the CDL manual, within how many feet of an oncoming vehicle, and within how many feet of a vehicle you are following, should you dim your headlights at night?
  40. According to the CDL manual, what is the best advice for driving in fog, and if driving is unavoidable, what should a driver do?
  41. After driving through deep standing water, what does the CDL manual say a driver should do to deal with wet brakes?
  42. A car ahead of you has its brake lights on near a freeway exit, as if the driver is unsure about taking the ramp. According to the CDL manual, at what point does this situation stop being just a hazard and become an emergency?
  43. Which of the following is specifically identified in the CDL manual as a blocked-vision hazard clue?
  44. Which combination of behaviors does the CDL manual list as clues to an impaired driver (sleepy, intoxicated, on drugs, or ill)?
  45. Per the Large Truck Crash Causation Study (LTCCS) cited in the CDL manual, what percentage of large-truck crashes involved the commercial driver being externally distracted?
  46. When using the controlled braking method to make an emergency stop, what should the driver do?
  47. A driver is using the stab braking method and the wheels lock up. What should the driver do next?
  48. According to the CDL manual, how should a driver perform a quick turn to avoid a crash and then get back into the original lane?
  49. An emergency forces a driver off the pavement onto the shoulder. What braking guidance does the CDL manual give before the vehicle comes to a stop or returns to the road?
  50. Which four factors does the CDL manual identify as the causes of a skid?
  51. A driver's rear wheels lock up under heavy braking and the back of the vehicle starts sliding sideways. According to the manual, how should the driver correct this drive-wheel skid?
  52. A driver is in a front-wheel skid, and the front end of the vehicle continues straight no matter how the steering wheel is turned. What does the CDL manual say is the only way to stop this skid?
  53. A driver's tractor is equipped with antilock braking systems (ABS). Which statement about ABS matches the CDL manual's guidance?
  54. According to the CDL manual, what is the main danger of a load with a high center of gravity (cargo piled up high or heavy items loaded on top), especially in curves or during a sudden swerve?
  55. How does the CDL manual say cargo should be arranged to help keep a vehicle's center of gravity low and handling safe?
  56. A load has shifted too far toward the rear of the trailer, leaving too little weight on the vehicle's steering axle. What problem does the CDL manual say this causes?
  57. What do federal regulations and the CDL manual require for securing cargo with tie-downs on a flatbed trailer?
  58. Using the AAMVA seven-step vehicle inspection method, which step comes immediately after inspecting the engine compartment?
  59. During a pre-trip inspection with the engine idling, what oil pressure gauge reading indicates the engine is operating within a normal range?
  60. Federal regulations require a driver to recheck cargo securement during a trip. After the initial check within the first 50 miles of the trip, how often must the driver reexamine the cargo and securement devices?
  61. Absent a vehicle equipped with circuit breakers, which combination of emergency equipment is federally required to be carried on a commercial motor vehicle?
  62. How many hazard classes make up the U.S. Department of Transportation's hazardous materials classification system?
  63. Under federal placarding rules, what are the size and visibility requirements for a hazmat placard displayed on a vehicle?
  64. A hazmat shipping paper lists a material's identification number as 'UN1203.' What does this number represent, and where should a driver look for emergency guidance tied to it?
  65. A driver without a hazardous materials (H) endorsement is transporting a small quantity of hazmat that falls below the federal placarding threshold. Which statement is accurate?
  66. What is the correct practice for selecting a gear before descending a steep mountain grade in a loaded combination vehicle?
  67. What is the 'snub braking' technique used to control vehicle speed on a long mountain descent?
  68. What is the purpose of a highway escape ramp (runaway truck ramp), and what should a driver do upon recognizing brake fade while descending a grade?
  69. According to NHTSA research cited in the AAMVA CDL Manual, approximately how many police-reported crashes occur each year in the U.S. due to drowsy driving?
  70. A driver who gets 6 hours of sleep or less before a shift faces what increased crash risk compared to a well-rested driver, and which additional factor further raises that risk?
  71. Which of the following is a recognized early warning sign of driver fatigue described in the AAMVA CDL Manual?
  72. What is the only effective way to counteract driver fatigue, according to the AAMVA CDL Manual?
Other practice categories:
Air Brakes Combination Vehicles Hazmat (H) Endorsement Tanker (N) Endorsement Doubles/Triples (T) Endorsement Passenger (P) Endorsement School Bus (S) Endorsement