49 CFR § 397.203 - Standards for determining preemption.

---
identifier: "/us/cfr/t49/s397.203"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "49 CFR § 397.203 - Standards for determining preemption."
title_number: 49
title_name: "Transportation"
section_number: "397.203"
section_name: "Standards for determining preemption."
chapter_name: "FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "B"
subchapter_name: "FEDERAL MOTOR CARRIER SAFETY REGULATIONS"
part_number: "397"
part_name: "TRANSPORTATION OF HAZARDOUS MATERIALS; DRIVING AND PARKING RULES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "49 U.S.C. 322; 49 CFR 1.87. Subpart A also issued under 49 U.S.C. 5103, 31136, 31502, and 49 CFR 1.97. Subparts C, D, and E also issued under 49 U.S.C. 5112, 5125."
regulatory_source: "36 FR 4876, Mar. 13, 1971, unless otherwise noted."
cfr_part: "397"
---


# 397.203 Standards for determining preemption.

(a) Any highway routing designation established, maintained, or enforced by a State, political subdivision thereof, or Indian tribe is preempted if—

(1) Compliance with both the highway routing designation and any requirement under the Act or of a regulation issued under the Act is not possible;

(2) The highway routing designation as applied or enforced creates an obstacle to the accomplishment and execution of the Act or the regulations issued under the Act; or

(3) The highway routing designation is preempted pursuant to § 397.69(b) of this part.

(b) [Reserved]

[57 FR 44132, Sept. 24, 1992, as amended at 59 FR 51834, Oct. 12, 1994]