🚛 100 TEXAS CDL WRITTEN TEST 2026 – QUESTIONS & ANSWERS

🔥GENERAL KNOWLEDGE (CORE CDL)

1. What is the maximum legal BAC for CDL drivers in Texas?

Answer: 0.04%
(Texas CDL DUI law 2026)

2. When must a CDL holder notify their employer of a traffic conviction?

Answer: Within 30 days

3. What is the maximum speed limit for trucks in Texas?

Answer: Posted speed limit, up to 85 mph where authorized

4. What does a diamond-shaped sign mean?

Answer: Warning

5. What is off-tracking?

Answer: Rear wheels follow a shorter path than front wheels

6. What is the minimum following distance for large trucks?

Answer: One second for every 10 feet of vehicle length

7. What does a solid yellow line mean?

Answer: No passing

8. What must you do before changing lanes in a CMV?

Answer: Signal, check mirrors, check blind spots

9. What is the purpose of a pre-trip inspection?

Answer: Ensure vehicle is safe to operate

10. What is the maximum tire tread depth required on steering axle?

Answer: 4/32 inch

AIR BRAKES
11. What happens when air pressure drops below 60 PSI?

Answer: Low air warning activates

12. What happens at approximately 20–45 PSI?

Answer: Spring brakes engage

13. What is brake fade?

Answer: Loss of braking power from overheating

14. What should you do if brakes get wet?

Answer: Apply light pressure while moving slowly

15. What is the purpose of the air compressor?

Answer: Build air pressure for braking system

COMBINATION VEHICLES
16. Which unit should be braked first?

Answer: Trailer

17. What causes trailer jackknife?

Answer: Trailer wheels lock up

18. Why should you avoid backing a combination vehicle?

Answer: Increased risk of jackknife

19. What is the safest way to stop a skid?

Answer: Release brakes and steer

20. What is a converter dolly?

Answer: Connects trailers in doubles/triples

SAFE DRIVING & SPEED CONTROL
21. What is the Texas Basic Speed Law?

Answer: Never drive faster than conditions allow

22. When should you downshift?

Answer: Before starting downhill

23. What is the proper braking technique on long downgrades?

Answer: Controlled or stab braking

24. What does hydroplaning cause?

Answer: Loss of traction

25. How can hydroplaning be reduced?

Answer: Reduce speed

HAZARDOUS MATERIALS (HAZMAT)
26. What is a placard?

Answer: Hazard warning sign on CMV

27. When are placards required?

Answer: When hauling regulated hazardous materials

28. What must you do if hazmat leaks?

Answer: Stop and secure area

29. What does a Class 3 placard indicate?

Answer: Flammable liquids

30. Who must have a TSA background check?

Answer: Hazmat endorsement holders

TANK VEHICLES
31. What is surge?

Answer: Liquid movement inside tank

32. What does surge affect most?

Answer: Braking and handling

33. What is the best way to control surge?

Answer: Smooth acceleration and braking

34. Why are tank vehicles harder to stop?

Answer: Shifting liquid weight

35. When is surge strongest?

Answer: Half-full tanks

DOUBLES & TRIPLES
36. What trailer should be in front?

Answer: Heaviest trailer

37. What increases rollover risk?

Answer: High center of gravity

38. What is the main danger of doubles/triples?

Answer: Rear trailer sway

39. What should you check before coupling?

Answer: Fifth wheel and locking jaws

40. What is the most common cause of rollovers?

Answer: Speed

TEXAS CDL RULES & LAWS
41. What is the minimum CDL age for intrastate driving in Texas?

Answer: 18 years old

42. What is the minimum CDL age for interstate driving?

Answer: 21 years old

43. What is required for railroad crossings?

Answer: Stop, look, and listen

44. Which vehicles must stop at railroad crossings?

Answer: Hazmat, buses, and tankers

45. What is the penalty for CDL DUI?

Answer: 1-year disqualification

INSPECTIONS & SAFETY
46. What must be checked during pre-trip inspection?

Answer: Brakes, lights, tires, steering

47. What does ABS warning light mean?

Answer: ABS malfunction

48. What should you do if ABS light stays on?

Answer: Continue driving with caution

49. What is the purpose of wheel chocks?

Answer: Prevent vehicle movement

50. What is a slack adjuster?

Answer: Adjusts brake slack

DRIVING CONDITIONS
51. When should you use low beams?

Answer: Fog, rain, snow

52. What is the danger of black ice?

Answer: Invisible and slippery

53. What should you do in high winds?

Answer: Reduce speed

54. What increases stopping distance?

Answer: Speed and weight

55. What is space management?

Answer: Maintaining safe space around vehicle

EMERGENCIES
56. What should you do if engine fails downhill?

Answer: Shift to lower gear

57. What is runaway truck ramp used for?

Answer: Emergency stopping

58. What should you do if tire blows out?

Answer: Hold steering wheel and slow gradually

59. What is the first step after a crash?

Answer: Secure the scene

60. What is required accident reporting time?

Answer: Immediately

NIGHT & WORK ZONES
61. What reduces night visibility?

Answer: Glare and fatigue

62. What is required in Texas work zones?

Answer: Obey reduced speed limits

63. What happens to fines in work zones?

Answer: Increased penalties

64. What does an orange sign mean?

Answer: Construction or maintenance

65. What is the safest night driving practice?

Answer: Reduce speed

COUPLING & UNCOUPLING
66. What should you check before coupling?

Answer: Kingpin and fifth wheel

67. What indicates proper coupling?

Answer: Locked jaws

68. What must you do before uncoupling?

Answer: Set parking brakes

69. What should you inspect after coupling?

Answer: Air lines and electrical

70. What prevents trailer separation?

Answer: Safety chains

GENERAL SAFETY & DEFENSIVE DRIVING
71. What is defensive driving?

Answer: Anticipating hazards

72. What causes most CMV crashes?

Answer: Driver error

73. What is lane drift?

Answer: Vehicle unintentionally leaving lane

74. What is the safest speed in rain?

Answer: Below posted limit

75. What should you do if fatigued?

Answer: Stop and rest

CDL ENDORSEMENTS & COMPLIANCE
76. What endorsement is needed for tank vehicles?

Answer: N endorsement

77. What endorsement is needed for hazmat?

Answer: H endorsement

78. What endorsement is needed for doubles/triples?

Answer: T endorsement

79. What is hours-of-service compliance?

Answer: Legal driving time limits

80. What is the maximum driving time per day?

Answer: 11 hours

FINAL KNOWLEDGE
81. What is the purpose of placards?

Answer: Identify hazardous materials

82. What does a leaking placard indicate?

Answer: Dangerous situation

83. What is cargo securement?

Answer: Prevent cargo movement

84. What increases rollover risk?

Answer: Speed in curves

85. What is mirror adjustment critical for?

Answer: Eliminating blind spots

86. What should you do before descending a hill?

Answer: Select proper gear

87. What is stab braking?

Answer: Apply brakes firmly then release

88. What causes brake fade?

Answer: Excessive heat

89. What should you do at uncontrolled intersections?

Answer: Yield appropriately

90. What is the purpose of CDL testing?

Answer: Ensure safe commercial drivers

91. What is required to carry hazardous materials?

Answer: Proper endorsement

92. What is a CMV?

Answer: Commercial Motor Vehicle

93. What is the safest way to enter traffic?

Answer: Yield and merge smoothly

94. What is skid recovery?

Answer: Regaining traction

95. What is the leading cause of jackknife?

Answer: Improper braking

96. What should you do if steering fails?

Answer: Slow gradually and stop safely

97. What does a flashing red signal mean?

Answer: Stop

98. What is the most important CDL skill?

Answer: Safety awareness

99. What must you always carry as a CDL driver?

Answer: Valid CDL and medical card

100. What is the goal of the Texas CDL written test?

Answer: Ensure safe, qualified commercial drivers

🔥
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