Correct answer: A – Dents or leaks
The tank's body or shell must be inspected for dents and leaks. The driver should also check beneath and around the vehicle for signs of leakage. Intake, discharge, and cut-off valves, pipes, connections, hoses, manhole covers, and vents are other important parts of the tank inspection.
Source: Commercial Driver License Manual — § 8.1.1, “Leaks”
Correct answer: C – A high center of gravity and movement of the liquid cargo
A high center of gravity makes a tank vehicle top-heavy and easier to roll over. Liquid cargo also moves within the tank, producing surge that affects handling. Baffles can reduce forward-and-back surge, but side-to-side movement can still occur and contribute to a rollover.
Source: Commercial Driver License Manual — §§ 8.2.1–8.2.2, “High Center of Gravity” and “Danger of Surge”
Correct answer: D – It works properly
Emergency shut-off systems are included among the special-purpose equipment that must be checked on an equipped tank vehicle. The driver must verify that the system works. The same operational check applies to other installed special-purpose equipment, such as vapor-recovery kits and grounding or bonding cables.
Source: Commercial Driver License Manual — § 8.1.2, “Check Special Purpose Equipment”
Correct answer: B – Liquid movement combined with a high center of gravity
Tank vehicles often carry much of their load high above the road, creating a high center of gravity. Liquid movement and surge can also change how the vehicle handles during starts, stops, and turns. Drivers must operate smoothly and take curves cautiously because these characteristics increase instability and rollover risk.
Source: Commercial Driver License Manual — § 8.2, “Driving Tank Vehicles”
Correct answer: D – 1,000 gallons
The federal CDL definition covers a commercial motor vehicle designed to transport liquid or gaseous material in tanks that each have a rated capacity above 119 gallons and have a combined rated capacity of at least 1,000 gallons. The tanks may be permanently or temporarily attached to the vehicle or chassis. At that threshold, a tank endorsement is required.
Source: 49 CFR § 383.5 – Definitions, Commercial Driver License Manual — § 1.1, “Commercial Driver License Tests—Tank Vehicle”
Correct answer: B – False
A cargo tank should never be loaded completely full. Liquid expands as it warms, so sufficient empty space—called outage—must be left in the tank. Different liquids require different amounts of outage, and the amount loaded must also account for the cargo's weight and applicable weight limits.
Source: Commercial Driver License Manual — §§ 8.2.6–8.2.7, “Outage” and “How Much to Load?”
