For a vehicle requiring a CDL, which attached liquid or gas tank capacities meet the federal tank-vehicle definition?
Correct answer: Each qualifying tank exceeds 119 gallons; combined capacity is at least 1,000 gallons
The federal definition uses rated tank capacity, not the quantity currently loaded, and includes permanent or temporary attachment. Its narrow exception covers an empty storage-container tank of at least 1,000 gallons that is not designed for transportation and is temporarily attached to a flatbed. An empty tank designed for transportation is not automatically exempt. Tank operation requires the applicable endorsement; hazardous cargo can require additional authorization.
Source: 49 CFR 383.5, Tank vehicle definition, actual eCFR versioner API response dated 2026-09-10; corroborating endorsement requirement in 383.93(b)(3), reviewed 2026-09-12 ↗
Under the federal CLP rule, what cargo restriction applies to a learner with a tank endorsement?
Correct answer: The tank must be empty and any previous hazardous-material residue purged
An N-endorsed CLP permits only an empty tank vehicle. A tank that previously contained hazardous material must be purged of residue. Other CLP conditions, including the qualified accompanying CDL holder, still apply.
Source: 49 CFR 383.25(a)(5)(iii), with supervisor condition in (a)(1); current eCFR displayed up to date September 10, 2026; reviewed September 12, 2026 ↗
Which cargo-tank defect can make it unsafe to transport a load?
Correct answer: A leaking valve or tank seam
Inspect the tank, valves, pipes, hoses and connections for leaks. Do not carry liquid or gas cargo in a leaking tank.
Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.1.1 Leaks, printed 8-1 (physical PDF page 131) ↗
What should a driver do after discovering that a cargo tank is leaking?
Correct answer: Do not transport cargo in it
Do not transport liquid or gas cargo in a leaking tank. Correct the leak before using the tank to carry cargo.
Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.1.1 Leaks, printed 8-1 (physical PDF page 131) ↗
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: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.1.1 Leaks — valves, printed 8-1 (physical PDF page 131) ↗
What should be checked at tank manhole covers and vents?
Correct answer: Sound gaskets, correctly closed covers, clear vents
Secure gasketed covers prevent leaks, while clear vents must remain able to function.
Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.1.1 Leaks — manhole covers and vents, printed 8-1 (physical PDF page 131) ↗
A tanker has vapor recovery, grounding cables and emergency shutoffs. What should the driver do before operating it?
Correct answer: Check that the installed special-purpose equipment works
Vapor recovery, grounding and bonding cables, emergency shutoffs, and built-in extinguishers require inspection.
Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.1.2 Check Special Purpose Equipment, printed 8-1 (physical PDF page 131) ↗
Which cargo-tank condition must be corrected before travel?
Correct answer: Open discharge valve or manhole cover
Discharge valves and manhole covers must be properly closed before travel. This does not mean blocking the vents; vents must remain clear and functional.
Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.1.1 Leaks — manhole covers and valves, printed 8-1 (physical PDF page 131) ↗
Which load characteristic contributes directly to a liquid tanker's rollover risk?
Correct answer: A high center of gravity
Much of the load weight is high above the road, making the vehicle top-heavy.
Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.2.1 High Center of Gravity, printed 8-1 (physical PDF page 131) ↗
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: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.2.1 High Center of Gravity, printed 8-1 (physical PDF page 131) ↗
What can liquid surge do after a partly filled tanker stops on a slippery road?
Correct answer: Shove the stopped vehicle forward
A moving liquid wave can strike the tank end and shove the vehicle in the wave direction.
Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.2.2 Danger of Surge, printed 8-2 (physical PDF page 132) ↗
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: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.2.3 Bulkheads, printed 8-2 (physical PDF page 132) ↗
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: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.2.4 Baffled Tanks, printed 8-2 (physical PDF page 132) ↗
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: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.2.5 Unbaffled Tanks, printed 8-2 (physical PDF page 132) ↗
Why are some food-product tanks built without baffles?
Correct answer: Baffles can make the inside difficult to clean to sanitation standards
Baffles can complicate thorough interior cleaning. The manual uses food-product tanks as an example of smooth-bore construction; this is not a blanket claim about every food cargo or every sanitation rule.
Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.2.5 Unbaffled Tanks, printed 8-2 (physical PDF page 132) ↗
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: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.2.6 Outage, printed 8-2 (physical PDF page 132) ↗
Which three factors does Pennsylvania CDL manual section 8.2.7 list for deciding how much liquid to load?
Correct answer: Expansion in transit, liquid weight, and legal weight limits
Allow expansion space and respect cargo weight and legal limits. Available tank volume alone does not determine a safe load.
Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.2.7 How Much to Load?, printed 8-2 (physical PDF page 132) ↗
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: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.2.7 How Much to Load?, printed 8-2 (physical PDF page 132) ↗
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: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.3.1 Drive Smoothly, printed 8-3 (physical PDF page 133) ↗
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: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), 8.3.2 Controlling Surge, printed 8-3 (physical PDF page 133) ↗
