For a vehicle requiring a CDL, which attached liquid or gas tank capacities meet the tank-endorsement threshold?
Correct answer: Each qualifying tank exceeds 119 gallons; combined capacity is at least 1,000 gallons
The threshold uses rated capacity: more than 119 gallons individually and at least 1,000 gallons in aggregate. A hazardous-material load may require additional authorization.
Source: Texas DL-7C, March 2026, section 8, PDF page 109: Tank endorsement ↗
When may a commercial learner permit holder with a tank endorsement operate a tank vehicle?
Correct answer: Only when it is empty, and a former hazardous load has been purged
A CLP holder may operate it only empty; a tank that previously carried hazardous material must also be purged.
Source: 49 CFR 383.25(a)(5)(iii): empty tank and hazardous-residue restrictions ↗
What is the most important condition to check on every tank vehicle?
Correct answer: Leaks
Leaks can make the vehicle unlawful and unsafe to move and can leave the driver responsible for cleanup.
Source: Texas DL-7C, March 2026, section 8, PDF page 109: Pre-trip inspection ↗
What should a driver do after discovering that a cargo tank is leaking?
Correct answer: Do not transport the liquid or gas in that tank
A leaking tank must not be driven with cargo; doing so is a crime and the vehicle can be placed out of service.
Source: Texas DL-7C, March 2026, section 8, PDF page 109: Leak response ↗
Before loading, unloading, or moving a tank vehicle, what must be verified about its valves?
Correct answer: They are in the correct positions
Intake, discharge, and cutoff valves must be checked for leaks and set correctly for the operation.
Source: Texas DL-7C, March 2026, section 8, PDF page 109: Valves ↗
What should be checked at tank manhole covers and vents?
Correct answer: Covers have sound gaskets and close correctly, and vents are clear
Secure gasketed covers prevent leaks, while clear vents must remain able to function.
Source: Texas DL-7C, March 2026, section 8, PDF page 109: Covers and vents ↗
Which system is special-purpose tanker equipment that must work when installed?
Correct answer: Emergency shutoff system
Vapor recovery, grounding and bonding cables, emergency shutoffs, and built-in extinguishers require inspection.
Source: Texas DL-7C, March 2026, section 8, PDF page 109: Special equipment ↗
Which cargo-tank condition must be corrected before travel?
Correct answer: An open cargo discharge valve or manhole cover
A tank vehicle must never be driven with valves or manhole covers open.
Source: Texas DL-7C, March 2026, section 8, PDF page 109: Safe condition ↗
Why are liquid tankers especially vulnerable to rollover?
Correct answer: Their load has a high center of gravity
Much of the load weight is high above the road, making the vehicle top-heavy.
Source: Texas DL-7C, March 2026, section 8, PDF page 109: Rollover risk ↗
How should a tanker driver approach highway, entrance-ramp, and exit-ramp curves?
Correct answer: Well below the posted curve speed
Tankers can roll even at posted curve speeds, so the driver must reduce speed well below them.
Source: Texas DL-7C, March 2026, section 8, PDF page 109: Curves ↗
What can liquid surge do after a partly filled tanker stops on a slippery road?
Correct answer: Push the stopped vehicle forward into an intersection
A moving liquid wave can strike the tank end and shove the vehicle in the wave direction.
Source: Texas DL-7C, March 2026, section 8, PDF page 110: Liquid surge ↗
When loading a tank divided into separate compartments by bulkheads, what deserves special attention?
Correct answer: Front-to-rear weight distribution
Separate compartments can overload the front or rear if their weight is distributed poorly.
Source: Texas DL-7C, March 2026, section 8, PDF page 110: Bulkheads ↗
What movement do baffles primarily help control?
Correct answer: Forward-and-back liquid surge
Holes in baffles reduce longitudinal surge; dangerous side-to-side movement remains possible.
Source: Texas DL-7C, March 2026, section 8, PDF page 110: Baffles ↗
Why must starts and stops be especially gentle with a smooth-bore tanker?
Correct answer: Nothing inside the tank slows the liquid flow
An unbaffled smooth-bore tank permits strong forward-and-back surge.
Source: Texas DL-7C, March 2026, section 8, PDF page 110: Smooth-bore tanks ↗
Why are some food-product tanks built without baffles?
Correct answer: Baffles can make the inside difficult to clean to sanitation standards
Sanitation requirements can rule out baffles because they complicate interior cleaning.
Source: Texas DL-7C, March 2026, section 8, PDF page 110: Food-grade tanks ↗
What does outage mean when loading a liquid cargo tank?
Correct answer: Empty space left for the liquid to expand
Liquids expand as they warm, so the tank must not be filled completely.
Source: Texas DL-7C, March 2026, section 8, PDF page 110: Outage ↗
Which three factors does the tank chapter list for deciding how much liquid to load?
Correct answer: Expansion, liquid weight, and legal weight limits
Allow expansion space and respect the cargo weight and legal limits. Available tank volume alone does not determine a safe load.
Source: Texas DL-7C, March 2026, section 8, PDF page 110: Loading limits ↗
Why might a large tank be only partly filled with a dense liquid?
Correct answer: A full tank could exceed legal weight limits
Tank volume does not override weight limits; dense products can make a full tank overweight.
Source: Texas DL-7C, March 2026, section 8, PDF page 110: Dense liquids ↗
Which driving pattern is safest for a loaded tanker?
Correct answer: Smooth starts, gradual stops, gentle turns, and steady lane changes
Smooth control limits surge and rollover forces created by the high center of gravity.
Source: Texas DL-7C, March 2026, section 8, PDF page 110: Smooth control ↗
How should a tanker driver brake for a planned stop?
Correct answer: Brake well in advance with steady pressure and extra following distance
Early, steady braking and more following room help keep surge controlled.
Source: Texas DL-7C, March 2026, section 8, PDF page 110: Surge control ↗
