An empty tank vehicle previously carried placard-required Class 3 flammable liquid. Does emptying the liquid by itself remove the 25-foot smoking restriction?
Correct answer: No; the rule also covers this empty tank vehicle.
The rule expressly covers an empty tank motor vehicle used for the specified flammable liquid or gas service when marking or placarding was required.
Source: 49 CFR 397.13(b); current eCFR text for covered operations, retrieved September 21, 2026; reviewed September 21, 2026. ↗
A truck containing covered hazardous materials stops to refuel its own fuel tank. What does the hazmat fueling rule require?
Correct answer: Engine off, with a person controlling the fueling at the fill point.
397.15 concerns fueling the motor vehicle itself. It requires the engine not to operate and a person to control the fueling process where the fuel tank is filled.
Source: 49 CFR 397.15(a)–(b); current eCFR text for covered operations, retrieved September 21, 2026; reviewed September 21, 2026. ↗
Before offering hazardous material in a package, who must ensure the package materials are compatible with its contents?
Correct answer: The offeror, as required by the packaging compatibility rule.
The offeror must ensure that the packaging is compatible with the hazardous material. A correct label or intact exterior does not by itself establish that the contents and packaging materials are compatible.
Source: 49 CFR 173.24(e)(1); current eCFR text for covered operations, retrieved September 21, 2026; reviewed September 21, 2026. ↗
A closed hazardous-material package has hazardous residue adhering to its outside. Does a tight closure alone make this acceptable for ordinary transport?
Correct answer: No; the general packaging rule also prohibits hazardous residue outside.
General packaging requirements include no hazardous-material residue adhering to the package exterior during transport. Preventing leakage through the closure does not excuse contamination already outside.
Source: 49 CFR 173.24(b)(4); current eCFR text for covered operations, retrieved September 21, 2026; reviewed September 21, 2026. ↗
When does the tire rule for covered hazardous-material vehicles require examination of each tire?
Correct answer: At the start of each trip and each time the vehicle is parked.
397.17(a) specifies trip-start and each-parking examinations. It does not replace the driver's other inspection duties.
Source: 49 CFR 397.17(a); current eCFR text for covered operations, retrieved September 21, 2026; reviewed September 21, 2026. ↗
A covered hazmat truck has a flat tire. Where may it be driven under the repair-location exception?
Correct answer: To the nearest safe place for the necessary repair.
The tire must be repaired, replaced or properly inflated before driving, except travel to the nearest safe place to perform that work. Other safe-operation requirements still apply.
Source: 49 CFR 397.17(b); current eCFR text for covered operations, retrieved September 21, 2026; reviewed September 21, 2026. ↗
A tire on a covered hazmat vehicle is found overheated. What must be resolved before further operation?
Correct answer: The cause of the overheating must be corrected.
The driver must cause the overheated tire to be removed to a safe distance and correct the cause before operating again. Arrange qualified help and maintain applicable parking and attendance precautions.
Source: 49 CFR 397.17(c)–(d); current eCFR text for covered operations, retrieved September 21, 2026; reviewed September 21, 2026. ↗
A Class 3 placard-required truck approaches an ordinary railroad grade crossing with no applicable exception. Where must it stop?
Correct answer: Between 15 and 50 feet from the tracks.
For a covered vehicle, stop within 50 feet but not closer than 15, then look and listen. Use a gear that allows crossing without shifting.
Source: 49 CFR 392.10(a), (a)(3)(vi); current eCFR text for covered operations, retrieved September 21, 2026; reviewed September 21, 2026. ↗
A cargo tank formerly used to transport hazardous material is empty. At an ordinary grade crossing with no applicable exception, does empty status alone remove the federal stop requirement?
Correct answer: No; the rule includes loaded and empty hazardous-material cargo tanks.
392.10(a)(4) expressly covers such cargo tanks whether loaded or empty. The specific crossing exceptions in paragraph (b) must be considered separately.
Source: 49 CFR 392.10(a)(4), (b); current eCFR text for covered operations, retrieved September 21, 2026; reviewed September 21, 2026. ↗
After making a required railroad stop, how should the driver choose a gear for crossing?
Correct answer: Choose one that allows the whole crossing without shifting.
The rule requires a gear that permits completing the crossing without a gear change and prohibits shifting while crossing.
Source: 49 CFR 392.10(a); current eCFR text for covered operations, retrieved September 21, 2026; reviewed September 21, 2026. ↗
Which shipping information helps responders locate the appropriate entry in the Emergency Response Guidebook?
Correct answer: The proper shipping name and material identification number.
The handbook explains that ERG information is indexed by proper shipping name and identification number. Accurate hazard communication helps responders find the applicable guidance.
Source: South Carolina Commercial Driver License Manual, body March 2025; 9.7.1, Emergency Response Guidebook, printed 9-15; physical PDF page 131; reviewed September 21, 2026. ↗
You notice an unfamiliar leak from hazardous cargo. How should you identify the material without deliberately exposing yourself?
Correct answer: Use available shipping information from a safe position.
Do not identify a hazardous leak by touching, tasting or deliberately smelling it. Use papers and safe observations, keep away and seek qualified emergency assistance.
Source: South Carolina Commercial Driver License Manual, body March 2025; 9.7.3, identifying and responding to leaks, printed 9-16; physical PDF page 132; reviewed September 21, 2026. ↗
A transportation incident meets 171.15's NRC telephone-report criteria. When must the person in physical possession notify the NRC?
Correct answer: As soon as practical, no later than 12 hours after occurrence.
The telephone deadline is as soon as practical and within 12 hours. This is not permission to delay emergency assistance; the detailed written report has a separate deadline.
Source: 49 CFR 171.15(a); eCFR current through September 17, 2026, read and reviewed September 21, 2026. ↗
A hazardous-material incident closes an interstate on-ramp for exactly one hour while the main lanes stay open. Does that meet the road-closure reporting trigger?
Correct answer: Yes; the one-hour-or-more rule includes access ramps.
PHMSA treats highway access ramps as parts of a major transportation artery. Closure for one hour or more can trigger NRC notice; exactly one hour qualifies, even when the main lanes remain open.
Source: PHMSA Hazardous Materials Incident Reporting FAQ, updated September 7, 2023; questions 5 and 16, 49 CFR 171.15(b)(1)(iv); reviewed September 21, 2026. ↗
After filing a required detailed hazardous-material incident report, how long must the reporting person retain a copy?
Correct answer: Two years, with the required access for an authorized DOT request.
The rule requires retaining a copy for two years at the principal place of business. If stored elsewhere, it must be made available there within 24 hours of an authorized DOT request. Filing does not remove the retention obligation.
Source: 49 CFR 171.16(b)(3); eCFR current through September 17, 2026, read and reviewed September 21, 2026. ↗
After an incident covered by 171.16, what is the ordinary deadline for the detailed hazardous-material incident report?
Correct answer: Within 30 days of discovering the incident.
The person in physical possession at the incident must submit the required DOT Form F 5800.1 within 30 days of discovery. This is separate from any prompt emergency call and NRC telephone notice.
Source: 49 CFR 171.16(a); eCFR current through September 17, 2026, read and reviewed September 21, 2026. ↗
