49 CFR Part 397 governs how a placarded hazardous materials load is driven, parked, attended, fueled and routed. It applies to any motor carrier transporting hazardous materials in a vehicle that must be marked or placarded, to every supervisory employee involved in that transportation, and to every person who operates or is in charge of the vehicle. Its hardest requirements are the attendance rule for explosives, the 300-foot parking setback, the 25-foot smoking radius, and the written route plan that must be prepared before a Division 1.1, 1.2 or 1.3 load moves.
49 CFR Part 397 is the on-the-road rulebook for placarded hazardous materials. It tells you where a hazmat load may and may not be parked, who has to be watching it and from how far away, what happens near open flames, how it gets fueled, and which routes it may legally take.
It sits on top of everything else. Under 49 CFR 397.2, a carrier subject to this part must comply with Parts 390 through 397 inclusive when transporting hazardous materials in a vehicle that must be marked or placarded under 49 CFR 177.823. Part 397 does not replace the hazardous materials regulations in 49 CFR Parts 171–180 — the shipping papers, packaging, marking, labeling and placarding rules live there. Part 397 governs the driving and the parking.
Who does Part 397 apply to?
49 CFR 397.1 reaches three groups: the motor carrier engaged in the transportation, each officer or employee of the carrier who performs supervisory duties related to that transportation, and each person who operates or is in charge of a motor vehicle containing hazardous materials. All three “must know and obey the rules in this part.”
The inclusion of supervisory employees matters. A dispatcher who routes a placarded load through a prohibited tunnel, or a terminal manager who lets an explosives trailer sit unattended overnight, is personally within the scope of the rule — not merely a witness to the driver’s violation.
49 CFR 397.3 adds the same precedence rule you see in Part 392: every vehicle containing hazardous materials must be driven and parked in compliance with the laws, ordinances and regulations of the jurisdiction in which it is operating, unless those are at variance with a specific DOT regulation that imposes a more stringent obligation or restraint.
What are the Part 397 distances and deadlines?
| Rule | The number | Citation |
|---|---|---|
| ”Attended” — how close the person in charge may be | On the vehicle, awake, not in a sleeper berth, or within 100 feet with the vehicle in unobstructed view | 49 CFR 397.5(d)(1) |
| Parking a Division 1.1/1.2/1.3 vehicle near the roadway | Not on or within 5 feet of the traveled portion of a public street or highway | 49 CFR 397.7(a)(1) |
| Parking a Division 1.1/1.2/1.3 vehicle near people | Not within 300 feet of a bridge, tunnel, dwelling, or building or place where people work, congregate or assemble | 49 CFR 397.7(a)(3) |
| Parking any other hazmat vehicle near the roadway | Not on or within 5 feet of the traveled portion, except brief operational necessity | 49 CFR 397.7(b) |
| Parking near an open fire | Not within 300 feet of an open fire | 49 CFR 397.11(b) |
| Smoking near a covered load | Not on or within 25 feet of the vehicle | 49 CFR 397.13 |
| Unattended explosives on a construction/excavation site | Bailee exception applies at 50 pounds or less of Division 1.1, 1.2 or 1.3 material | 49 CFR 397.5(b) |
| Retention of the driver’s signed receipt for explosives documents | One year | 49 CFR 397.19(c) |
| Class 7 route plan delivery to the shipper, non-exclusive-use shipments | Within fifteen working days following departure | 49 CFR 397.101 |
| Reporting a Class 7 route deviation | Within 30 days following the deviation | 49 CFR 397.101 |
| Class 7 driver training currency | Written training within the two preceding years | 49 CFR 397.101 |
| Deadline for a State or tribe to complete an NRHM routing designation after notice | 18 months | 49 CFR 397.71(b) |
What does the attendance rule actually require?
49 CFR 397.5 is the section that most often surprises carriers new to explosives work.
A motor vehicle containing Division 1.1, 1.2 or 1.3 material must be attended at all times by its driver or a qualified representative. “Attended” is defined precisely: the person in charge is on the vehicle, awake and not in a sleeper berth, or is within 100 feet of the vehicle with it in an unobstructed field of view. A driver asleep in the bunk is not attending the vehicle, and a driver inside a truck stop restaurant with the trailer around the corner is not either.
A “qualified representative” is a person designated by the carrier who is aware of the nature of the material, has been instructed in emergency procedures, is authorized to move the vehicle, and has the means and ability to do so.
397.5(b) provides the practical exceptions. The vehicle need not be attended when it is on the property of a motor carrier, the shipper or the consignee, in a safe haven, or — for 50 pounds or less of Division 1.1, 1.2 or 1.3 material — on a construction or excavation site, provided the bailee has been informed of the contents and emergency procedures and the vehicle remains within the bailee’s unobstructed field of view or in a safe haven. A safe haven is defined in 397.5(d)(3) as an area specifically approved in writing by local, State or Federal governmental authorities for the parking of unattended vehicles containing Division 1.1, 1.2 or 1.3 materials.
For every other hazardous material, 397.5(c) requires that a vehicle located on a public street or highway or the shoulder of a public highway be attended by its driver — except that the driver may leave the vehicle briefly when necessarily engaged in the duties of the driver’s occupation, but not for meals or rest breaks unless the vehicle is on the carrier’s, shipper’s or consignee’s property.
Where can a placarded truck legally park?
49 CFR 397.7 splits the question by hazard class.
Explosives (Division 1.1, 1.2, 1.3). The vehicle must not be parked:
- on or within 5 feet of the traveled portion of a public street or highway;
- on private property, including a filling station, without the knowledge and consent of the person in charge of the property, who must be made aware of the nature of the cargo; or
- within 300 feet of a bridge, tunnel, dwelling, or building or place where people work, congregate or assemble — except for brief periods when the necessities of operation require the vehicle to be parked and make it impracticable to park anywhere else.
All other hazardous materials. 397.7(b) prohibits parking on or within 5 feet of the traveled portion of a public street or highway, except for brief periods when the necessities of operation require the vehicle to be parked. The 300-foot setback does not apply outside the explosives divisions.
Fires. 49 CFR 397.11 adds a separate prohibition that applies to any vehicle containing hazardous materials: it must not be operated near an open fire unless the driver has first taken precautions to ascertain that the vehicle can safely pass the fire without stopping, and it must not be parked within 300 feet of an open fire.
What are the fueling, smoking and tire rules?
Three short sections carry outsized weight in incident investigations.
Fueling. 49 CFR 397.15 requires that when a vehicle containing hazardous materials is being fueled, the engine must not be operating, and a person must be in control of the fueling process at the point where the fuel tank is filled. Note the contrast with the general rule in 49 CFR 392.50, which permits running the engine “when it is necessary to run the engine to fuel” the vehicle. Under 397.15 there is no such allowance.
Smoking. 49 CFR 397.13 prohibits smoking or carrying a lighted cigarette, cigar or pipe on or within 25 feet of a motor vehicle containing Class 1 material, Class 5 material, or flammable material classified as Division 2.1, Class 3, Division 4.1 or Division 4.2 — and of an empty tank motor vehicle that has been used to transport Class 3 flammable liquids or Division 2.1 flammable gases and that required marking or placarding when loaded.
Tires. 49 CFR 397.17 requires the driver to examine each tire on the vehicle at the beginning of each trip and each time the vehicle is parked. If a tire is found flat, leaking or improperly inflated, it must be repaired, replaced or properly inflated before the vehicle is driven — although the vehicle may be driven to the nearest safe place to do that work. If a tire is found overheated, the driver must immediately cause it to be removed and placed at a safe distance from the vehicle, and must not operate the vehicle until the cause of the overheating is corrected. Compliance with 397.17 does not relieve the driver of the attendance and parking duties in 397.5 and 397.7.
That parking-time tire check is more demanding than the equipment inspection duties in 49 CFR 392.7 or the tire standards in Part 393. Every stop is an inspection point.
What are the routing rules?
Part 397 handles routing in two separate subparts.
Subpart C — non-radioactive hazardous materials (NRHM). 49 CFR 397.65 defines NRHM as a non-radioactive hazardous material transported in types and quantities that require placarding under Table 1 or Table 2 of 49 CFR 172.504. 49 CFR 397.67 then requires:
- A motor carrier or driver transporting NRHM must comply with the NRHM routing designations of a State or Indian tribe.
- A carrier or driver transporting placarded hazardous materials must operate over routes that do not go through or near heavily populated areas, places where crowds are assembled, tunnels, narrow streets or alleys — except where there is no practicable alternative, where a reasonable deviation is necessary to reach terminals, points of loading and unloading, facilities for food, fuel, repairs or rest, or a safe haven, or where an emergency condition or a law enforcement directive requires it. Operating convenience is not a basis for that determination.
- For Division 1.1, 1.2 or 1.3 explosives, the carrier must prepare a written route plan and furnish a copy to the driver. When the trip begins at a location other than the carrier’s terminal, the driver may prepare the plan as the carrier’s agent.
49 CFR 397.71 sets the federal standards a State or tribe must satisfy before it may establish, maintain or enforce an NRHM routing designation — including a public-safety finding, a 30-day public comment opportunity, 60-day written notice to affected neighboring jurisdictions, through-routing between adjacent areas, and reasonable access to terminals, loading points and facilities for food, fuel, repairs, rest and safe havens.
Subpart D — Class 7 (radioactive) materials. 49 CFR 397.101 requires carriers and drivers to operate on routes that minimize radiological risk, considering accident rates, transit time, population density and activities, and time of day and day of week. Highway route controlled quantity shipments must move only over preferred routes. The carrier must prepare a written route plan and supply a copy to the driver before departure and a copy to the shipper — before departure for exclusive-use shipments, or within fifteen working days following departure otherwise — including origin and destination, planned stops, and telephone numbers that will access emergency assistance in each State. Deviations must be reported within 30 days, and the driver must have received written training within the two preceding years, with the training certificate kept in the driver qualification file described in Part 391.
What do inspectors actually check under Part 397?
Hazmat inspections are documentation-heavy, and Part 397 items are checked alongside the shipping paper review.
- The route plan. For explosives, the inspector asks for the written plan and compares it against where the truck actually is. A missing plan under 397.67(d) is straightforward to write.
- The document package. Under 397.19, the driver must possess a copy of the Part 397 rules and the emergency instructions document, and must be familiar with them. Inspectors ask questions to test that familiarity.
- Where the vehicle is parked, right now. The 5-foot and 300-foot setbacks in 397.7 are measured on the spot. A placarded explosives trailer parked at a truck stop 200 feet from the restaurant is a violation the inspector can document with a rangefinder.
- Attendance. If the driver walked away from a placarded vehicle on a public shoulder, that is a 397.5(c) violation regardless of how long they were gone.
- Placarding and marking, which triggers Part 397 applicability in the first place under 397.2 and 49 CFR 177.823.
- Tire condition, cross-referenced against 397.17 and the tread depth thresholds in 49 CFR 393.75.
In an office compliance review, the auditor asks a different question: does the carrier have a system? They look for written routing procedures, evidence that supervisory employees were trained, the retained receipts required by 397.19(c), and — for carriers holding a hazardous materials safety permit — the records that permit requires. Carriers running placarded freight alongside general freight usually need driver credentials, endorsement expirations and route documentation tracked per load rather than per year, which is where a compliance and safety system earns its keep against a shared spreadsheet.
What are the most common Part 397 violations?
Part 397 violations are lower in volume than Part 393 equipment defects, but they carry high severity weights and they attract enforcement attention because the consequence of the underlying conduct is severe.
- Failure to attend a placarded vehicle, 397.5. Almost always a driver leaving a load on a public shoulder or at an unapproved lot for a meal or rest.
- Improper parking, 397.7. The 300-foot setback is routinely violated at truck stops and rest areas, where the geometry simply does not permit compliance — which is why route planning has to identify the parking, not just the roads.
- No written route plan for explosives, 397.67(d).
- Driver not in possession of, or not familiar with, the required documents, 397.19.
- Smoking violations, 397.13, including the frequently forgotten application to empty flammable-liquid tanks.
- Fueling with the engine running, 397.15.
- Routing violations, 397.67(b), typically a tunnel or a restricted urban route taken for time.
How do you operate hazmat cleanly under Part 397?
Plan the parking with the route. The 300-foot rule and the attendance rule together mean an explosives run has to be planned around approved stopping points and safe havens before dispatch, not discovered by a tired driver at midnight. Build the stop list into the written route plan.
Train the supervisors, not only the drivers. 397.1 puts supervisory employees inside the rule. Dispatchers need to know that operating convenience is not a lawful basis for a routing decision under 397.67(b).
Keep the paperwork the regulation names. The signed receipt under 397.19(c) is retained for one year. The Class 7 route plan goes to the shipper on the schedule in 397.101 and deviations are reported within 30 days. These are dated obligations, and a missed date is an easy finding.
And treat hazmat as an overlay, not a substitute. Everything in Part 395 hours of service, Part 393 equipment and Part 392 driving rules still applies in full. For the wider context, see our FMCSA regulations guide, the DOT compliance guide, and the full 49 CFR reference library. Fleets managing placarded and non-placarded freight in the same yard generally end up formalizing this in a fleet compliance tracking workflow.
This page is a plain-English summary of 49 CFR Part 397 and is not legal advice. Hazardous materials transportation is also governed by 49 CFR Parts 171–180. Always read the current regulation text and consult qualified counsel for your specific operation.
Note: This is a plain-English summary of 49 CFR Part 397, current as of the date above, and is general information rather than legal advice. The regulation itself is controlling — read it on the eCFR and confirm current requirements with the FMCSA.