FMCSR 393.40(a) – Inadequate Brakes: Citations & Out-of-Service Rules

No, most likely not. Across our 13 million inspection records, 393.40(a) citations result in an out-of-service order only 0.2% of the time—just 1 OOS placement out of 403 total citations. That's far below the 31.4% average OOS rate across all FMCSR codes. However, inadequate brakes are a safety issue, so an inspector may still require immediate repair before you continue operating.

A single 393.40(a) citation carries a severity weight of 8 points. Under the CSA scoring system, this violation is weighted into your Unsafe Driving BASIC over a rolling 30-month period. Multiple citations within that window will compound, so if you've received more than one in recent months, your BASIC score will be higher. Check your FMCSA Safety & Fitness Electronic Records (SAFER) account to see your current total.

First, do not operate the vehicle until brakes are inspected and repaired. Second, document the repair with a certified mechanic—get written proof of what was corrected. Third, contact your carrier's safety manager and notify your insurance company. Fourth, if you believe the citation is factually incorrect (inspector misidentified a component or the test was performed wrongly), you have the right to contest it through FMCSA's DataQs system within 90 days. Keep all inspection reports and work orders.

In the vehicle maintenance category, 393.40(a) is less commonly cited than related violations. Our database shows 404 all-time citations, ranking #992 of 3,036 FMCSR codes. By comparison, slack adjuster defects (393.47E) account for 180,363 citations, and inoperable lamps (393.9) have 180,097. However, 393.40(a)'s 0.2% OOS rate is extremely low compared to general maintenance violations like 396.3(a)(1) at 45.3% OOS. This suggests inspectors cite it conservatively.

Yes. If you believe the citation is incorrect—for example, the inspector failed to properly test your brakes, misidentified a component, or violated your due process rights—you can file a DataQs challenge within 90 days of the citation. FMCSA will review roadside inspection documentation, repair records, and maintenance logs. Contestations work best when you have evidence: mechanic's reports, service dates, or witness accounts. Document everything immediately after the stop.

Very rare recently. Our inspection data shows 0 citations for 393.40(a) in the last 12 months and 0 in the last 90 days. All 404 citations in our database are historical. This suggests either brake inspection standards have improved across the industry, or inspectors are citing related violations (like slack adjuster defects) instead. Regardless, brake maintenance remains critical—don't interpret low citation volume as less importance.

DODGE vehicles account for 116 citations, followed by FORD (59), FREIGHTLINER (59), and INTERNATIONAL (32). These represent older or medium-duty trucks where brake component wear is more common. If you operate one of these models, prioritize proactive brake inspections every 30,000 miles and keep detailed service records. Early detection of worn pads, leaks, or air system issues prevents roadside citations.

Under FMCSA's CSA program, vehicle violations like 393.40(a) are recorded against the carrier's USDOT number, not the driver. However, they can affect hiring, insurance, and your carrier's inspection frequency and safety audits. If you're an owner-operator, the citation is tied to your entity. As a company driver, the violation reflects on your employer's safety profile. Either way, maintain personal records of all maintenance and repairs you authorize or complete.