49 CFR Part 397: Hazmat Driving, Parking & Equipment Rules
What §397 requires of drivers and carriers hauling placardable hazmat, and the in-cab equipment those rules imply
Last updated: April 27, 2026
Overview
49 CFR Part 397 governs the driving and parking of motor vehicles transporting hazardous materials. It is one of three federal hazmat rule sets a fleet has to reconcile. Part 172 covers labeling, marking, and placarding. Part 177 covers carriage by motor vehicle. Part 397 picks up where the cargo is loaded and the truck is moving: who can leave the vehicle, where it can park, what routes it can take, and what no one can do near it.
Part 397 is enforced by FMCSA at roadside inspections and post-incident audits. It applies on top of (not instead of) the broader fleet-DOT rule set, including the cab-equipment requirements in 49 CFR §393.95 (10 B:C extinguisher for placarded vehicles, warning devices, no open-flame signals on Class 1 explosives loads). The full Part 397 text is published in Title 49, Part 397 of the Electronic Code of Federal Regulations.
The short version
A driver hauling Class 1 explosives in Divisions 1.1, 1.2, or 1.3 must keep the vehicle attended at all times. Any placarded hazmat vehicle has parking setbacks (5 feet from the traveled portion, 300 feet from bridges, tunnels, dwellings, and gathering places for explosives loads). Smoking is prohibited within 25 feet of vehicles loaded with Class 1, Class 5, Class 3, Division 2.1, or Divisions 4.1 / 4.2 materials. Class 1 loads also need a written route plan.
Attended Vehicle Rule (§397.5)
§397.5 is the rule drivers ask about most: when can the truck be left alone? The answer depends on what is in the trailer.
- Division 1.1, 1.2, 1.3 explosives: the vehicle must be attended at all times by its driver or a qualified representative of the motor carrier.
- "Attended" definition: the responsible person must be on the vehicle (awake, and not in a sleeper berth) or within 100 feet of the vehicle with it in their unobstructed field of view.
- Other placarded hazmat: the vehicle must be attended by the driver while on a public street or highway, except for duties that are incident and necessary to operating the vehicle.
- Limited unattended exceptions for explosives: on motor carrier property, on shipper or consignee property, in a designated safe haven, or (for 50 lb or less) at a construction or survey site, when the lawful bailee is aware of the materials and instructed in emergency procedures.
The "awake, and not in a sleeper berth" qualifier is the part that catches most long-haul Division 1.1 drivers off guard. Carriers running explosives loads should review the full §397.5 text plus their own internal safe-haven and driver-relief procedures.
Parking Rules (§397.7)
§397.7 splits parking restrictions into two tiers: a strict tier for Division 1.1, 1.2, and 1.3 explosives, and a baseline tier for all other placarded hazmat.
| Cargo | Setback from traveled roadway | Setback from bridges, tunnels, dwellings, gathering places | Private property |
|---|---|---|---|
| Division 1.1, 1.2, 1.3 explosives | Not within 5 ft | Not within 300 ft, except briefly when operationally necessary | Only with knowledge and consent of the person in charge, who is aware of the nature of the materials |
| Other placarded hazmat | Not within 5 ft | No federal 300-ft setback (state and local rules may apply) | Permitted, subject to driver attendance under §397.5 |
Division 1.1, 1.2, 1.3 explosives
Traveled roadway: Not within 5 ft of traveled portion
Setback: Not within 300 ft of bridges, tunnels, dwellings, or places where people work, congregate, or assemble
Private property: Only with knowledge and consent of the person in charge, who is aware of the materials
Other placarded hazmat
Traveled roadway: Not within 5 ft of traveled portion
Setback: No federal 300-ft rule (check state and local)
Private property: Permitted, subject to §397.5 attendance
The 300-foot rule is the trap that costs explosives carriers the most. It applies to bridges, tunnels, dwellings, and any place where people work, congregate, or assemble. A truck stop dining room counts. A loading dock with people on it counts. The brief operational exception (loading, unloading, brief stops in traffic) is narrow.
Routing & Tunnels (§397.67 to §397.71)
Subpart D of Part 397 covers route planning. The rules are heaviest for Class 1 explosives and for non-radioactive hazardous material (NRHM) routes designated by states or tribes.
- §397.67 Class 1 written route plan: the carrier (or the driver, when the trip begins away from a terminal) must prepare a written route plan for any vehicle hauling Division 1.1, 1.2, or 1.3 explosives. The plan must avoid heavily populated areas, places where crowds gather, tunnels, narrow streets, and alleys when a practicable alternative exists. Operating convenience is not a basis for non-compliance.
- §397.69 NRHM route designations: states and Indian tribes can designate specific highway routes over which non-radioactive hazmat may or may not be transported, subject to federal standards in §397.71.
- §397.71 federal standards for NRHM routes: a designated route must enhance public safety, allow public participation (30 day comment period, hearings as needed, newspaper notice), notify and consult affected jurisdictions at least 60 days before implementation, preserve continuity of movement between adjacent jurisdictions, provide reasonable access to terminals and to fuel, food, repair, rest, and safe-haven facilities, and consider population density, highway type, quantities, emergency response, terrain, weather, congestion, and accident history.
- Tunnels: route plans for explosives loads have to avoid tunnels where a practicable alternative exists. Many states and bridge or tunnel authorities also impose their own placard-by-placard prohibitions on top of the federal rules.
The driver has to carry the written route plan in the cab on Class 1 trips and produce it on demand. A misplaced or out-of-date plan is the most common §397.67 violation at roadside.
Smoking & Open Flame (§397.13)
No smoking within 25 feet of placarded loads of certain classes
§397.13 prohibits any person from smoking or carrying a lighted cigarette, cigar, or pipe within 25 feet of a motor vehicle that contains Class 1, Class 5, Class 3 (flammable liquids), Division 2.1 (flammable gases), or Division 4.1 or 4.2 materials. The same 25-foot rule applies to empty tank vehicles that were last loaded with Class 3 flammable liquids or Division 2.1 flammable gases.
The smoking rule is the simplest of the §397 driver rules and the one most often cited at fueling islands and rest stops. It overlaps with 49 CFR §393.95(f): a Division 1.1, 1.2, or 1.3 explosives load cannot use open-flame warning devices (fusees or liquid-burning flares) at a disabled-vehicle stop. Reflective triangles only.
Required Equipment Implied by §397
Part 397 does not list cab equipment line by line. It assumes the equipment in Parts 392, 393, and 177 is already on the truck. A driver enforcing §397 in real time is leaning on the following items, each of which has its own standards page.
- Fire extinguisher (10 B:C minimum for placarded vehicles): 49 CFR §393.95. A 10 lb ABC dry chemical unit is the most common spec.
- Warning devices (reflective triangles only on explosives): 49 CFR §393.95(f). Three triangles meeting FMVSS 125. Fusees and flares are prohibited near Class 1 loads.
- Spill response kit sized to the cargo: not a federal §397 mandate by itself, but practically required by §177.804 (driver duty to protect the public on a release) and by carrier safety policy. See the Hazmat Spill Kit Selection Guide for sorbent chemistry and sizing by hazard class.
- PPE for the cargo class: at minimum, gloves and eye protection that match the materials placarded under 49 CFR §172.504.
- Emergency Response Guidebook (ERG): drivers carrying hazmat placards keep the current edition in the cab for first-response reference.
- Shipping papers and emergency response information: carried within the driver's reach per §177.817, and required by §397 for any pre-trip and roadside review.
- First aid kit: not federally specified for §397, but carried under most fleet safety policies and ANSI/ISEA Z308.1 truck-class lists. Pair with the Fleet & DOT Compliance Guide for the full cab-equipment checklist.
Spill Containment in Stock
Picking the right sorbent chemistry
Oil-only sorbents float on water and absorb petroleum, fuel, and oil while rejecting water (Class 3 flammable liquid spills outdoors). Universal sorbents pick up oil, water, and most non-aggressive chemicals (broad-spectrum cab use). HazMat sorbents are formulated for aggressive chemicals including acids, bases, and unknowns (Class 8 corrosives). The Hazmat Spill Kit Selection Guide walks the chemistry decision by USDOT hazard class, with sizing by gallon load.
Frequently Asked Questions
Does 49 CFR Part 397 apply to my truck?
Part 397 applies to any motor vehicle transporting hazardous materials in quantities that require placarding under §172.504, plus a few specific explosives and radioactive scenarios. If the vehicle is placarded, Part 397 applies. If the load is below placarding thresholds and not on the §172.504 Table 1 always-placard list, most of Part 397 does not apply.
Can a driver sleep in the truck while hauling explosives?
No. §397.5 defines an attended vehicle as one where the responsible person is on the vehicle awake and not in a sleeper berth, or within 100 feet with the vehicle in their unobstructed field of view. A driver in a sleeper berth on a Division 1.1, 1.2, or 1.3 load is not attending the vehicle as defined.
How far does a placarded truck have to park from a bridge or tunnel?
The 300-foot setback in §397.7 applies to vehicles transporting Division 1.1, 1.2, or 1.3 explosives. Other placarded hazmat is not subject to the federal 300-foot rule, but state and local restrictions and bridge or tunnel authority rules often add their own placard-class prohibitions on top of the federal baseline. All placarded vehicles still have to keep at least 5 feet from the traveled portion of any public roadway.
How close can someone smoke to a placarded hazmat truck?
§397.13 prohibits smoking or carrying a lighted cigarette, cigar, or pipe within 25 feet of a vehicle loaded with Class 1, Class 5, Class 3, Division 2.1, or Division 4.1 or 4.2 materials. The same 25-foot rule applies to empty tank vehicles that last carried Class 3 flammable liquids or Division 2.1 flammable gases. Other classes are not covered by this specific rule, but a fueling-island posted no-smoking zone usually extends well past 25 feet.
Does Part 397 require a written route plan?
Yes, but only for Division 1.1, 1.2, and 1.3 explosives. §397.67 requires the carrier (or the driver, when the trip begins away from a terminal) to prepare a written route plan and furnish it to the driver before the trip. The plan has to avoid heavily populated areas, places where crowds gather, tunnels, narrow streets, and alleys where a practicable alternative exists. Other placarded hazmat does not need a §397.67 route plan, but states or tribes can designate non-radioactive hazmat (NRHM) routes under §397.69 that the carrier is then bound to follow.
Are fusees or flares allowed for a hazmat breakdown on the highway?
Not on Division 1.1, 1.2, or 1.3 explosives loads. §392.25 and §393.95(f) require reflective triangles meeting FMVSS 125 in that scenario, never fusees or liquid-burning flares. Other placarded loads can technically use fusees during a roadside breakdown, but most carriers standardize on triangles across the fleet to avoid the open-flame fact pattern near Class 3 flammable liquids.
Does §397 require a spill kit on the truck?
Part 397 does not list a spill kit in the federal text. The practical requirement comes from §177.804 (driver duty to protect the public on a release), most state hazmat permits, and carrier insurance policy. A sorbent kit sized to the cargo and matched to the hazard class is the standard answer. The Hazmat Spill Kit Selection Guide walks the chemistry and sizing decision.
What is a "safe haven" under §397.5?
A safe haven is a designated parking area where unattended Division 1.1, 1.2, or 1.3 explosives vehicles are permitted under conditions in §397.5. Local authorities approve safe havens. They are listed in carrier safety planning documents and at terminal dispatch points; a driver who needs to break for rest on an explosives load and is not on motor carrier or shipper property should locate a designated safe haven rather than a public truck stop.
Outfitting a hazmat fleet?
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