The Most Common Truck Inspection Violations (Ranked by What Actually Hurts Your Score)

A carrier pulls up their BASIC scores and sees Vehicle Maintenance at the 72nd percentile. They know they need to fix something. They look at the violation with the highest severity weight on their record: a tire tread depth violation at severity 8. They focus all their attention on tires.

Meanwhile, brake adjustment violations (severity 6 each) have appeared on 5 of their last 12 inspections. Each individual brake violation carries a lower severity weight than the tire violation. But 5 occurrences at severity 6 produce a total weighted score of 30 (before time weighting), compared to 8 for the single tire violation. The brake violations are doing nearly four times the BASIC score damage, and the carrier is ignoring them because they're fixated on the highest individual severity weight.

This is the mistake most carriers make when reading their violation history. They focus on the most severe individual violations when they should be focused on the violations producing the most total BASIC score damage. And total damage is frequency times severity, not severity alone.

Here are the violations that produce the most total BASIC score impact across the industry, ranked by the combination of how often they're cited and how much each citation costs:

The violations at the top of that list aren't there because each one is the most severe. They're there because they appear constantly in inspection data and produce cumulative BASIC score damage that exceeds the one-time impact of rarer, higher-severity violations.

Vehicle Maintenance Violations: The Category That Catches Everyone

Vehicle Maintenance is the most commonly triggered BASIC in the entire CSA system. It has an intervention threshold of 80%, and the violations that drive carriers toward that threshold are overwhelmingly in three systems: brakes, lights, and tires. Read our BASIC scores guide for how each BASIC category works and the tier hierarchy for broker vetting.

Brake Violations: The #1 BASIC Score Killer

Brake deficiencies are the single largest category of vehicle violations nationally. They appear in a significant percentage of all Level 1 inspections, and many of them result in out-of-service orders.

Brakes out of adjustment (severity 6). The most commonly cited brake violation. Inspectors measure brake stroke (the distance the brake pushrod travels when the brakes are applied). If the stroke exceeds the adjustment limit for that brake type, the brake is cited as out of adjustment. On a tractor-trailer combination with 10 brake chambers, one or two being out of adjustment is common enough that this violation appears on millions of inspection reports annually.

Why it's so damaging: Each occurrence carries severity 6, and the violation is cited frequently. A carrier with brake adjustment violations on 4 of 15 inspections accumulates a time-weighted violation score that pushes their Vehicle Maintenance BASIC up faster than almost any other violation type.

Brake hose/tubing chafing, restricted, or worn (severity 4). Air brake systems use hoses and tubing that rub against frame components, axles, and other parts during normal operation. Over time, this chafing wears through the outer covering and eventually compromises the hose. Inspectors check for worn spots, abrasion damage, and hoses that are positioned where they'll continue to wear.

Air compressor not working or leaking (severity 7). The air compressor powers the entire brake system. When it fails or leaks significantly, the truck cannot maintain adequate braking pressure. This is a high-severity violation because it affects the entire braking system, not just one wheel position. An OOS violation almost every time.

What carriers should do about brakes: Establish a brake adjustment schedule that's shorter than what you think you need. Inspectors find brakes out of adjustment because the adjustment interval is too long, not because brake adjusters are failing. Checking and adjusting brake stroke every 10,000 to 15,000 miles (rather than waiting for the manufacturer's maximum interval) prevents the most commonly cited violation in the entire FMCSA system. Read our CSA score improvement guide for the full strategy ranked by speed of BASIC score impact.

Lighting Violations: Low Severity, High Volume

Lighting violations are individually minor (severity 1 to 2) but they're cited constantly. Inoperative headlamps, taillights, turn signals, marker lights, reflectors, and clearance lights are among the most frequently documented violations in the system.

Inoperative required lamp (severity 2). Any required light that's not working: headlight, taillight, brake light, turn signal, clearance lamp, or marker lamp. This is one of the most commonly cited violations across all inspection types.

Damaged or missing reflective tape (severity 1). Federal regulations require retroreflective tape on the sides and rear of trailers. Missing, peeling, or damaged tape is a low-severity citation that adds up when it appears on multiple inspections.

Why lighting violations matter more than their severity suggests: Individual lighting violations carry severity 1 or 2. A single citation barely moves a BASIC percentile. But when a carrier has lighting violations on 6 of 20 inspections, the cumulative effect adds 6 to 12 points of severity-weighted score to their Vehicle Maintenance BASIC. For a small carrier, that's enough to push the percentile up by 10 to 15 points.

What carriers should do about lights: Walk-around light check before every trip. Every light on the tractor and every light on the trailer. Five minutes. Zero cost. This eliminates an entire category of violations that, individually, seem insignificant but collectively push BASIC scores up through sheer volume. Check any carrier's violation patterns with our inspection history tool, which shows recurring violation types across inspections and flags patterns automatically.

Tire Violations: High Severity Per Occurrence

Tire violations carry higher individual severity weights than most other vehicle violations, and they frequently result in out-of-service orders.

Tire tread depth below minimum (severity 8). The federal minimum tread depth is 4/32" for steer tires and 2/32" for drive and trailer tires. Inspectors measure tread depth in the major grooves. A tire at 1/32" on a drive axle is below the 2/32" minimum and results in a severity-8 violation and a vehicle OOS order.

Flat tire or audible air leak (severity 8). A tire that's flat or losing air visibly is an immediate OOS violation. Less common than tread depth violations but carries the same severity weight.

What carriers should do about tires: Replace tires before they reach the minimum tread depth, not after. A steer tire at 5/32" passes inspection today. At 3/32" next week, it's a severity-8 violation that sits on your record for 24 months. The cost of early replacement is far less than the BASIC score damage from a tire violation, especially for small carriers where one violation moves the percentile significantly. Read our OOS rate guide for how tire and brake violations affect out-of-service rates relative to the national average.

Driver Fitness Violations: The Administrative Failures

Driver Fitness violations are almost entirely administrative. They reflect paperwork and credential management failures, not dangerous driving behavior. The BASIC threshold is 80%, and the violations that push carriers toward it are highly preventable.

The Violations That Drive Driver Fitness Scores

No or expired medical certificate (severity 4). Every CDL holder must have a current DOT medical certificate. When the certificate expires and the driver hasn't renewed it, any inspection that checks driver credentials will cite this violation. It's one of the most commonly cited driver-side violations because medical certificates expire on fixed dates and carriers that don't track expiration dates miss them.

Operating without a valid CDL (severity 4 to 8). Driving without the correct CDL class, driving with an expired CDL, or driving without required endorsements. The severity depends on the specific deficiency. Wrong class or missing endorsement is severity 4. No CDL at all is severity 8.

No driver qualification file maintained (severity 2). The carrier is required to maintain a qualification file for each driver containing their application, road test certificate, MVR, medical certificate, and other documents. Inspectors verify the driver's credentials at roadside, and administrative gaps in the carrier's files are cited during compliance reviews. Read our compliance review guide for what FMCSA examines during an on-site audit.

What carriers should do about Driver Fitness: Calendar every expiration date. Medical certificates, CDLs, endorsements. Set alerts at 90, 60, and 30 days before expiration. Audit driver qualification files quarterly. These violations are entirely preventable with an administrative process that takes one afternoon per quarter.

HOS Compliance Violations: The Operational Problems

HOS violations feed into the HOS Compliance BASIC (threshold 65%) and reflect how the carrier manages driving time, rest periods, and ELD compliance. Read our HOS rules guide for the current rules and why the 14-hour window, not the 11-hour limit, is what actually ends most driving days.

The Violations That Drive HOS Scores

Driving beyond the 11-hour limit (severity 7). The driver exceeded the maximum 11 hours of driving time after their last 10-hour off-duty period. With ELD mandate enforcement, this violation now reflects actual driving time exceedances rather than logbook paperwork errors, which makes it a stronger safety signal than the same violation would have been in the paper-logbook era.

Driving beyond the 14-hour on-duty window (severity 7). The driver drove after the 14th consecutive hour since coming on duty. The 14-hour window runs continuously and cannot be paused by breaks. This violation often results from dock delays, traffic, and dispatch planning that doesn't account for non-driving on-duty time.

No ELD or ELD not functioning (severity 5). The driver doesn't have a functioning ELD or is using a device that doesn't meet the technical specifications. Less common now that the ELD mandate has been in full effect for several years, but still appears when devices malfunction or when carriers use non-compliant devices.

30-minute break violation (severity 4). The driver continued driving after 8 cumulative hours without taking the required 30-minute break. Lower severity than the driving-time violations but still contributes to the HOS BASIC.

What carriers should do about HOS: Look at dispatch planning before looking at driver behavior. If your drivers consistently violate the 14-hour window, the problem is probably that transit times don't account for dock waits, fueling, and breaks. Fix the schedule before blaming the driver.

Unsafe Driving Violations: The Behavioral Signals

Unsafe Driving violations have the strongest correlation with crash risk and feed into the BASIC with the strictest threshold (65%). These violations are the hardest to fix because they involve changing human behavior rather than replacing a brake component or renewing a medical certificate. Read our BASIC scores guide for why Unsafe Driving is the Tier 1 BASIC that brokers should check first.

The Violations That Drive Unsafe Driving Scores

Speeding (severity 7 to 10). The severity depends on how far over the limit. Speeding 6 to 10 mph over is severity 7. Speeding 11 to 14 over is severity 8. Speeding 15+ over is severity 10, the maximum. A single speeding citation at 15+ over carries the highest possible severity weight and can push a small carrier's Unsafe Driving BASIC up by 20 to 30 percentile points.

Failure to use seatbelt (severity 7). Cited during driver-side inspections when the driver is observed not wearing a seatbelt. Severity 7 is high for what many drivers consider a minor personal choice, but FMCSA's crash correlation data shows that unbelted drivers have significantly worse outcomes in accidents.

Following too closely (severity 5). Cited when an inspector or law enforcement observes the driver tailgating. Less commonly cited than speeding but still a regular Unsafe Driving violation.

Texting or using a handheld device (severity 10). Maximum severity. Using a handheld mobile phone while operating a CMV is one of the most heavily penalized driving behaviors in the CSA system. A single citation can devastate a small carrier's Unsafe Driving BASIC.

What carriers should do about Unsafe Driving: Speed limiters prevent the highest-severity violation in the system (speeding 15+ over). In-cab cameras with real-time coaching reduce speeding, following distance, and distracted driving violations over time. Progressive discipline for moving violations gives drivers an incentive structure. This is the hardest BASIC to fix because you're changing behavior, not replacing parts.

A Worked Example: Which Violations to Fix First

Carrier: 20 trucks, Vehicle Maintenance BASIC at 68th percentile. 28 inspections in 24 months. 11 violations total.

Violation breakdown:

What the carrier fixates on: The tire violation (severity 8) because it has the highest individual severity weight.

What the carrier should fix first: Brake adjustment. Four occurrences at severity 6 produce a total weighted score roughly 3x higher than the single tire violation. Fixing the brake adjustment interval prevents the violation that's doing the most total damage to their BASIC score.

The priority order based on total BASIC impact:

1. Brake adjustment (total severity 24, recurring, preventable with shorter adjustment intervals)
2. Brake hose chafing (total severity 8, recurring, preventable with routing inspection)
3. Tire tread depth (total severity 8, single occurrence, preventable with earlier replacement)
4. Lighting (total severity 6, recurring but low individual impact, preventable with pre-trip)
5. Cargo securement (total severity 2, single occurrence, lowest priority)

Use our BASIC Score Improver, which shows each violation driving your BASIC percentile alongside its severity weight, time weight, and estimated score impact of removal. This is the tool that helps carriers identify which violations to address first based on total BASIC score cost, not individual severity.

The Pre-Trip Inspection: 10 Minutes That Prevent 80% of Vehicle Violations

The majority of vehicle violations cited during roadside inspections are for defects that a thorough pre-trip inspection would catch. Lights. Tires. Brakes. Air system. Coupling devices. Cargo securement. These aren't hidden problems. They're problems a driver walking around the truck with a flashlight and an air gauge would find in 10 minutes.

What a Real Pre-Trip Catches

Lights: Walk around the truck and trailer with the headlights on, turn signals active, and brakes applied. Every inoperative light is visible. Five minutes of checking eliminates the entire category of lighting violations.

Tires: Visual check for damage, tread depth (use a gauge, not your eyes), and inflation. A tire that's visibly low or has tread at the wear bars needs attention before it becomes a severity-8 citation.

Brakes: Check brake stroke on each wheel position (pry bar method or brake stroke indicator if equipped). If any pushrod extends beyond the adjustment limit, adjust before departure. Inspect air hoses and tubing for chafing, cracks, and leaks.

Air system: With the engine off and system charged, listen for air leaks. Check the low-pressure warning. Perform the brake system tests (static and applied pressure drop tests).

Coupling: Check the fifth wheel connection, kingpin engagement, and slider locks. Verify the trailer air and electrical connections.

Carriers who enforce genuine pre-trip inspections (the kind that take 10 minutes, not the kind that take 30 seconds in the cab) consistently outperform their peers on Vehicle Maintenance. The cost is zero. The time is 10 minutes per departure. The alternative is a severity-6 or severity-8 violation that sits on the record for 24 months.

Frequently Asked Questions

What are the most common DOT truck inspection violations?

Brake out of adjustment is the most commonly cited violation in roadside inspections. Lighting deficiencies (inoperative lamps, damaged reflective tape) are the most frequently cited by volume. Tire tread depth violations, HOS violations (driving beyond the 11-hour limit), and expired medical certificates round out the top five. Read our inspection history guide for how to read violation patterns across inspections.

Which truck inspection violations are most likely to cause an out-of-service order?

Brake deficiencies (out of adjustment, air leaks, missing components), tire violations (below minimum tread depth, flat tires), and HOS violations (driving beyond limits) are the most common causes of out-of-service orders. A violation that results in OOS means the inspector determined continued operation was unsafe. Read our OOS rate guide for how OOS rates compare to national averages.

How do inspection violations affect my CSA score?

Each violation feeds into the relevant BASIC category with its assigned severity weight (1 to 10) and time weight (full weight under 6 months, two-thirds at 6 to 12 months, one-third at 12 to 24 months). Your BASIC percentile reflects your total weighted violation score ranked against peers. High-severity, frequent, recent violations have the largest impact. Read our CSA score guide for the full calculation mechanics.

What is the severity weight of a brake violation?

Brake violations range from severity 4 (brake hose chafing) to severity 7 (air compressor failure). Brake out of adjustment is severity 6. The individual severity is moderate, but brake violations are cited so frequently that their cumulative BASIC score impact often exceeds that of higher-severity violations that occur less often.

Can I dispute a truck inspection violation?

Yes, through FMCSA's DataQs system, but only when the violation contains a factual error (wrong DOT number, violation code that doesn't match the inspector's narrative, incorrectly attributed inspection). You cannot dispute a violation because you disagree with the inspector's measurement. Read our DataQs guide for which violations are worth challenging.

What do truck inspectors check in a Level 1 inspection?

A Level 1 inspection covers driver credentials (CDL, medical certificate, HOS records), vehicle mechanical condition (brakes, tires, lights, suspension, steering, coupling devices, exhaust, cargo securement), and safety equipment. It's the most thorough inspection type and includes under-vehicle examination. A clean Level 1 is the strongest positive signal in a carrier's inspection record.

How long do inspection violations stay on my record?

Violations remain on your FMCSA record for 24 months from the inspection date. They carry full weight in BASIC calculations for the first 6 months, two-thirds weight from 6 to 12 months, and one-third weight from 12 to 24 months. After 24 months, they drop off entirely.

What is the most expensive truck inspection violation?

In terms of BASIC score damage, the most expensive violation is the one that occurs most frequently on your specific record, not the one with the highest individual severity weight. A severity-6 brake violation that appears 5 times costs more BASIC points than a severity-10 speeding violation that appears once. Check which violations are costing you the most with our BASIC Score Improver, which ranks violations by total score impact.

Bottom Line

The carrier fixating on their single severity-8 tire violation while ignoring four severity-6 brake violations is making a decision based on the wrong metric. Individual severity tells you how bad one violation is. Frequency times severity tells you how much total damage a violation type is doing to your BASIC score. And the violations doing the most total damage are almost always the moderate-severity ones that keep showing up because the root cause hasn't been fixed.

Fix the violations you see most often, not the violations that look worst on paper. The brake adjustment that appears on every third inspection is costing you more than the tire violation that appeared once. And the 10-minute pre-trip that would have caught both costs nothing.