Part 397 — Transportation of Hazardous Materials: Driving and Parking Rules
49 CFR Part 397: Driving, parking, and attendance rules specific to commercial vehicles hauling hazardous materials.
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49 CFR Part 397 establishes the driving and parking rules specifically applicable to commercial motor vehicles transporting hazardous materials. While the broader hazardous materials regulations are governed by PHMSA (Parts 100-185), Part 397 addresses the FMCSA-enforced operational aspects — how hazmat vehicles must be driven, where they can park, and who must be present to attend them.
The attendance requirements under Part 397 are among the most operationally demanding. Vehicles transporting Division 1.1, 1.2, or 1.3 explosives must be attended at all times while stopped — the driver must remain within 100 feet of the vehicle and have it in clear view, unless an attendant is present. Other hazardous materials categories also carry attendance requirements when the vehicle is parked, though with less strict proximity rules.
Route restrictions under Part 397 prohibit hazmat vehicles from using certain tunnels and may require pre-approved routing for the most dangerous materials. Carriers transporting placarded quantities of hazardous materials must comply with applicable highway routing regulations, which vary by state and by the specific materials being transported.
Key Provisions
- Division 1.1, 1.2, and 1.3 explosive vehicles must be attended at all times when stopped.
- Route restrictions apply to certain hazmat loads — tunnel and highway routing rules vary by material.
- Drivers must have emergency response information accessible while transporting hazardous materials.
- Fueling of hazmat vehicles requires the engine to be off and a qualified attendant present.
- Smoking is prohibited within 25 feet of any vehicle carrying flammable materials.
Why It Matters to Truck Owners
Any commercial truck that hauls hazardous materials — fuel tankers, chemical carriers, propane deliveries, explosive transport — operates under both PHMSA hazmat regulations and Part 397’s driving and parking rules. A driver who parks a hazmat load unattended in violation of Part 397 creates both a federal violation and a serious public safety risk. If you’re buying a tank truck or a carrier that transports hazardous materials, understanding Part 397’s operational requirements is essential.
Frequently Asked Questions
What types of hazardous materials require vehicle attendance under Part 397?
Vehicles transporting Division 1.1, 1.2, or 1.3 explosives must be attended at all times — the driver must remain within 100 feet with the vehicle in clear view. Other categories of hazardous materials have attendance requirements specifically when the vehicle is parked on a public street or highway, generally requiring that the vehicle not be left unattended in ways that create a public hazard.
Are there route restrictions for hazmat trucks?
Yes — certain hazardous materials are subject to routing restrictions. Explosive vehicles have specific tunnel restrictions. States and localities may establish hazmat routing requirements through the federal highway routing program. Carriers must determine applicable routing requirements before transporting placarded hazardous materials through affected jurisdictions.
Do I need a hazmat endorsement to drive a truck hauling hazardous materials?
Yes — under Part 383, drivers transporting hazardous materials in quantities requiring placarding must hold an H endorsement on their CDL. Obtaining the H endorsement requires a background check through TSA and a knowledge test. The endorsement must be renewed with each CDL renewal and requires background re-vetting.
Read the official legal text: 49 CFR Part 397 — eCFR.gov (official)
Related Federal Trucking Laws
- Part 393 — Parts and Accessories for Safe Operation
- Part 391 — Driver Qualifications
- Hazardous Materials Regulations (49 CFR Parts 100-185)
This page is provided for informational purposes only and is not legal advice. Always verify current requirements at fmcsa.dot.gov or with a qualified transportation attorney.
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