Knowledge Practice Exam Questions

CDL Tanker & HazMat (X) Written Knowledge Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary hazard of driving a tanker with liquid cargo?
• Tire wear
• Slow acceleration
• Liquid surge and rollover
• Reduced fuel efficiency

Rationale: Liquid cargo moves inside the tank, which can cause

sudden shifts affecting vehicle stability and increasing the risk of rollover.

• Which type of hazardous material requires placarding for transport?
• Only flammable liquids 1 / 4

• All materials listed in the Hazardous Materials Table
• Only corrosive liquids
• Only explosives

Rationale: All hazardous materials listed by the DOT require placards

to alert others and emergency responders to the risk.

• What is the safest way to stop a tanker in an emergency?
• Slam on brakes immediately
• Pump brakes slowly while turning the wheel
• Apply controlled braking without abrupt steering
• Shift to neutral and coast to stop

Rationale: Abrupt braking or steering can cause a liquid surge,

leading to loss of control. Controlled braking reduces this risk.

• When carrying hazardous materials, which document must always

accompany the shipment?

• Vehicle registration
• Shipping papers
• Insurance certificate
• Driver logbook

Rationale: Shipping papers provide information on the type,

quantity, and emergency measures for hazardous cargo.

• Which of the following is a required inspection for tank vehicles before

driving?

• Tire rotation check 2 / 4

• Tank and liquid handling equipment inspection
• Engine oil top-off only
• Interior cleaning

Rationale: Inspecting the tank, valves, and other liquid-handling

equipment is essential to prevent leaks and accidents.

• What is the maximum speed for tank vehicles on most highways?
• 70 mph
• 65 mph or as posted
• 75 mph
• 60 mph in all states

Rationale: Tankers have lower speed limits due to liquid surge and

rollover risk; always follow posted speed limits.

• Which hazard class includes flammable gases?
• Class 1
• Class 3
• Class 2
• Class 4

Rationale: Class 2 materials are gases, which can be flammable, non-

flammable, or toxic.

• When approaching a railroad crossing with a tank vehicle carrying

hazardous materials, you must:

• Cross quickly to avoid blocking traffic
• Stop only if lights are flashing 3 / 4

• Stop within 15–50 feet of the nearest rail
• Maintain speed if the tracks are clear

Rationale: Federal regulations require tank vehicles carrying

hazardous cargo to stop at railroad crossings for safety.

• What effect does a liquid surge have in a partially filled tanker?
• Improves braking
• Can cause sudden shifts affecting steering and stability
• Reduces fuel consumption
• None, if driving straight

Rationale: Liquid moves in the tank, creating momentum that can

destabilize the vehicle, especially during turns or braking.

• When transporting flammable liquids, what is the main risk

during loading or unloading?

• Tire wear
• Sloshing of the liquid
• Static electricity ignition
• Engine overheating

Rationale: Static electricity can ignite flammable vapors during fuel

transfer; grounding and bonding the tank is required.

• What must you do if a hazardous materials spill occurs?
• Ignore if small
• Sweep it into the street
• Call emergency responders and follow your emergency plan
• / 4