FMCSR 393.19 Hazard Warning Signal Inoperable: Driver Q&A

No — almost certainly not. Across 30,339 all-time citations for 393.19, only 65 vehicles were placed out of service, giving this code a 0.2% OOS rate. For context, the average OOS rate across all FMCSR codes in our inspection database is 31.4%, so 393.19 sits far below the national average. The code is not OOS-eligible by designation, meaning inspectors have very little authority to park your truck solely for an inoperable hazard warning flasher. That said, if the same inspection surfaces a more serious violation alongside it, that other code could still trigger an OOS order.

393.19 carries a severity weight of 3 on the FMCSA CSA scoring scale. That base score is then multiplied depending on how recently the violation occurred — violations in the most recent 6 months receive the highest time-weight multiplier, violations between 6 and 12 months old receive a reduced multiplier, and anything older than 12 months ages out of your SMS percentile calculation entirely. Because this falls under the Vehicle Maintenance BASIC, the points accrue against the carrier's BASIC percentile and are visible to shippers, brokers, and enforcement. Fixing the flasher before your next inspection stops further point accumulation immediately.

Get the hazard flasher repaired before your next dispatch and document it. Here's what the co-occurrence pattern from our inspection records tells you to check at the same time:

1. Turn signals — 393.9TS appeared alongside 393.19 in 1,395 of the last 90 days' shared inspections. If the flasher is bad, the turn signal circuit is often bad too.
2. All required lamps — 393.9 co-occurred in 921 inspections; do a full lamp walk-around.
3. Windshield — 393.78 showed up in 450 shared inspections; inspect for cracks or obstructions.
4. Emergency equipment — 393.95A appeared in 255 inspections; verify your fire extinguisher is present and charged.
5. Fuel system — 396.5B co-occurred in 253 inspections; check for leaks while the hood is up.

Get a repair receipt dated before your next pre-trip and keep it in the cab.

Relatively minor, but don't ignore it. Among peer codes in the same Vehicle Maintenance category, 393.19's 0.2% OOS rate is one of the lowest. Compare it to 393.9(a) — Inoperable Required Lamps — which carries a 15.4% OOS rate across 660,737 citations, or 396.3(a)(1) — general inspection and maintenance — which hits a 45.3% OOS rate. Even the broad 393.9 code runs a 6.9% OOS rate across 180,097 citations. So while a broken hazard flasher rarely parks a truck, the peer violations that tend to accompany it are far more serious. Inspectors who find 393.19 are already looking closely at your lighting system.

Yes, you can submit a DataQs Request for Data Review (RDR) for any roadside inspection finding. Because 393.19 is an equipment violation — not a documentation issue — a successful challenge typically requires evidence that the hazard warning system was actually functioning at the time of the inspection. That could mean a repair invoice showing the unit passed inspection immediately before the stop, a mechanic's statement, or shop records showing no fault present. Submit your RDR through the FMCSA DataQs portal within the standard review window. If the challenge is upheld, the violation is masked from your SMS BASIC calculation. Carriers with multiple 393.19 citations — some have accumulated more than 100 all-time — benefit most from reviewing each record for accuracy.

Texas by a wide margin, followed by Georgia and Arizona. In the last 180 days, our inspection records show Texas issued 3,454 citations for 393.19 — dwarfing every other state. Georgia came in second at 142 citations, and Arizona third at 114. New Mexico (97), Pennsylvania (83), and New York (69) round out the next tier. Texas's dominance is likely tied to the high volume of cross-border commercial traffic at ports of entry along the U.S.-Mexico corridor, which also explains why the top cited carriers are predominantly Mexican-registered fleets. If you operate in Texas regularly, a functioning hazard flasher is a pre-trip priority.

Enforcement is running at a high and steady level — fix it before your next inspection. Over the last 12 months, our database recorded 9,983 citations for 393.19, and the last 90 days alone produced 2,128. Monthly citation counts over that stretch have stayed consistently in the 800–950 range. While the OOS rate remains low at 0.2%, the volume signals that inspectors are actively writing this violation rather than issuing warnings. Ranking #96 out of 3,036 FMCSR codes by all-time citation volume confirms it's a frequently enforced code. A $10–$30 flasher relay repair eliminates the exposure entirely; the CSA severity weight of 3 stacks up fast if you accumulate multiple hits across inspections.

It follows the carrier primarily, but the driver record is also tagged. Under FMCSA's CSA methodology, equipment violations like 393.19 — which fall under the Vehicle Maintenance BASIC — are attributed to the carrier's BASIC score because the carrier bears responsibility for keeping the vehicle in safe operating condition. The driver's inspection record will still show the citation, which can affect driver-specific SMS visibility and hiring background checks. This means both parties have skin in the game: carriers should build hazard flasher checks into their pre-trip inspection protocols, and drivers should document any pre-existing defects on their DVIR before leaving the yard to protect themselves from violations on equipment they didn't create.