393.42(a) Parking Brake Defective — Enforcement & Impact

Not automatically, but it's a significant risk. Across our inspection records, 393.42(a) resulted in an out-of-service order 30.1% of the time (196 out of 652 citations all-time). That's slightly below the all-FMCSR average of 31.4%, meaning this violation is a coin flip for roadside placement. The other 456 citations allowed continued operation after citation. If your parking brake is deemed unsafe to hold the vehicle stationary, expect a real chance of being placed OOS on the spot.

393.42(a) carries a CSA severity weight of 6 points. The actual points added to your Safety Management Cycle depends on the inspection outcome and the 30-day rolling window—FMCSA multiplies violations within 30 days of the same code. If this is your first 393.42(a) in 30 days, you'll add 6 points to the Vehicle Maintenance BASIC. Repeat violations within 30 days will increase the multiplier and your point total significantly.

Immediate steps:

1. Do not operate the vehicle if placed OOS—stop driving immediately.
2. Contact your carrier's maintenance team or a qualified repair facility today.
3. Have the parking brake system inspected and repaired to ensure it can hold the vehicle stationary on a grade.
4. Request a re-inspection by the same or another CVSA-certified inspector once repairs are complete.
5. Document all repair work and keep receipts for your CSA record.
6. If you believe the citation was issued in error, consider contacting your carrier's DataQs administrator to file a challenge within 90 days of the inspection date.

393.42(a) is relatively rare in enforcement. Our database shows only 652 all-time citations, ranking it #836 out of 3,036 FMCSR codes—well below high-volume codes like 393.9(a) (inoperable lamps: 660,737 citations). However, when ranked against similar vehicle maintenance violations, 393.42(a) sits in the middle: its 30.1% OOS rate exceeds 393.47E (slack adjuster defective: 0.0% OOS) but trails 396.3(a)(1) (inspection/repair/maintenance general: 45.3% OOS). Parking brake defects are taken seriously because they directly affect vehicle control.

Yes, you can file a DataQs (Data Quality System) challenge if you believe the inspection finding is inaccurate. Since 393.42(a) is an equipment defect finding, contestability depends on whether the inspector correctly applied the standard—that your parking brake could not adequately hold the vehicle stationary. DataQs challenges must be filed within 90 days of the inspection date through FMCSA's RDR (Roadside Data Recording) system. Contact your carrier's safety or compliance team to initiate the challenge; they typically manage the process on your behalf.

The trend is quiet. Our records show zero citations for 393.42(a) in the last 90 days and zero in the last 12 months, despite 652 all-time citations. This suggests the violation was cited historically but is now uncommon in roadside enforcement—possibly because parking brake standards are well-understood or because defects are being caught during routine maintenance. However, do not let low enforcement volume lull you into skipping parking brake inspections; if cited now, you face a 30.1% OOS risk.

Ford trucks dominate the citation history, with 111 citations across our records. DODGE follows with 39 citations, and FREIGHTLIN with 34. These are primarily lighter-duty and medium-duty trucks, not large over-the-road tractors. If you operate a Ford-based commercial vehicle (box truck, dump truck, or service vehicle), ensure your parking brake is inspected regularly. The data suggests parking brake defects appear more often on certain makes, possibly due to design or maintenance patterns in fleets using those vehicles.

Both. Under FMCSA CSA rules, this violation records against both your driver profile (Vehicle Maintenance BASIC) and your carrier's profile. If you're an owner-operator, the impact is entirely yours. If you're a company driver, your carrier's safety record suffers along with your own, which can trigger increased inspection scrutiny and affect fleet insurance and compliance ratings. Work with your carrier's safety team to resolve the citation and demonstrate corrective action.