49 CFR § 393.19 - Hazard warning signals.

---
identifier: "/us/cfr/t49/s393.19"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "49 CFR § 393.19 - Hazard warning signals."
title_number: 49
title_name: "Transportation"
section_number: "393.19"
section_name: "Hazard warning signals."
chapter_name: "FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "B"
subchapter_name: "FEDERAL MOTOR CARRIER SAFETY REGULATIONS"
part_number: "393"
part_name: "PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION"
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. 31136, 31151, 31502; sec. 1041(b), Pub. L. 102-240, 105 Stat. 1914, 1993; secs. 5301 and 5524, Pub. L. 114-94, 129 Stat. 1312, 1543, 1560; and 49 CFR 1.87."
regulatory_source: "33 FR 19735, Dec. 25, 1968, unless otherwise noted."
cfr_part: "393"
---


# 393.19 Hazard warning signals.

The hazard warning signal operating unit on each commercial motor vehicle shall operate independently of the ignition or equivalent switch, and when activated, cause all turn signals required by § 393.11 to flash simultaneously.

[70 FR 48046, Aug. 15, 2005]