What to Expect During a DOT Inspection

Every commercial motor vehicle operating across state lines is subject to the regulations set forth by the Federal Motor Carrier Safety Administration (FMCSA). At the heart of this oversight is the Department of Transportation (DOT) inspection—a thorough review of both vehicle condition and driver compliance. Understanding what to expect during a DOT inspection is critical for ensuring safe operations on the road.

The Different Levels of DOT Inspections

The DOT doesn’t take a one-size-fits-all approach. In fact, there are six levels of inspections—each with its own focus and intensity. The most commonly encountered ones are Levels I through III.

Level I: North American Standard Inspection

This is the most comprehensive and often the most time-consuming. A certified inspector examines both the driver and the vehicle.

Driver-specific checks include:

• Commercial driver’s license (CDL)
• Medical examiner’s certificate
• Driver’s record of duty status (logbook)
• Hours of service (HOS) compliance
• Alcohol and drug use indicators
• Seat belt usage

Vehicle-specific checks include:

• Brake system
• Tires, wheels, and rims
• Coupling devices
• Fuel and exhaust systems
• Frame integrity
• Lighting devices
• Steering and suspension
• Windshield wipers
• Emergency exits (for passenger carriers)
• Cargo securement

Expect the inspector to crawl under the vehicle, measure pushrod travel on brake chambers, and check for air leaks, chafed airlines, or oil contamination on linings.

Level II: Walk-Around Driver/Vehicle Inspection

This level is similar to Level I, but without the undercarriage inspection. Inspectors will review documentation and conduct a walk-around to assess visible defects or violations. It’s still extensive but less intrusive.

Level III: Driver-Only Inspection

Focuses solely on the driver's credentials, logs, and observable behaviors. The vehicle itself won’t be inspected unless something looks suspicious. This level is common at weigh stations or roadside stops when time is limited.

Level IV and Beyond

• Level IV: Special one-time inspections (often for data collection).
• Level V: Vehicle-only inspections conducted without the driver present, often at fleet yards.
• Level VI: Inspections of radiological shipments (specific to HAZMAT haulers).

How to Prepare for a DOT Inspection

Preparation begins long before you reach a scale house or roadside checkpoint. Proactive preventive maintenance and compliance reviews are key.

Pre-Trip Inspections Matter

Drivers are required to complete pre-trip and post-trip inspections. These should cover:

• Brake function and air pressure build-up time
• Condition of hoses and electrical lines between tractor and trailer
• Lights and reflectors
• Tire tread depth and inflation
• Fifth wheel locking mechanism
• Emergency equipment (fire extinguisher, triangles, spare fuses)

If you identify any defect, it must be addressed and documented before the vehicle hits the road. Ignoring a seemingly minor issue like a cracked mirror or faded clearance light can easily trigger a violation.

Documentation Must Be Accessible and Up-To-Date

Inspectors expect to see:

• Up-to-date CDL
• Current medical certificate
• Daily vehicle inspection reports (DVIRs)
• ELD logs
• Insurance documents
• Annual inspection certificate
• IFTA and IRP permits (if applicable)

Ensure these are organized in a binder or digital system that’s easy to access. Missing or incomplete paperwork often leads to unnecessary delays—or worse, out-of-service orders.

Common Causes for Vehicle Violations

Certain infractions show up again and again during roadside checks. Knowing the most frequent culprits allows operators to stay ahead of problems.

Brakes and Brake Adjustment

Brake-related issues remain the number one cause of out-of-service violations. Inspectors routinely check for:

• Worn or contaminated brake linings
• Inoperative service brakes
• Improper pushrod stroke length
• Audible air leaks

Heavy-duty trucks use compressed air systems with components like slack adjusters, chambers, and S-cams that must function in harmony. Technicians must ensure automatic slack adjusters are not over-extended, and that brakes are adjusted within legal limits.

Lighting Violations

From turn signals to license plate lights, all exterior lighting must function correctly. Inspectors pay close attention to:

• Inoperable lights
• Incorrect bulb color
• Cracked or missing lenses
• Non-reflective tape on trailers

Given how simple and affordable lighting fixes are, they represent low-hanging fruit for shops and operators.

Tire and Wheel Assembly

Inspectors will verify:

• Tread depth (minimum of 4/32" on steer tires, 2/32" elsewhere)
• Inflation pressure
• Exposed cords or sidewall damage
• Missing or loose lug nuts
• Cracked or bent rims

A tire blowout at highway speed is a catastrophic risk, and DOT inspectors are trained to spot signs of imminent failure.

Suspension, Steering, and Frame

A visual inspection will uncover:

• Cracked, broken, or shifted leaf springs
• Worn kingpins or tie rod ends
• Loose U-bolts
• Frame corrosion or fractures

Suspension systems like air ride or leaf spring setups must provide stable support and pass stress tests.

What Happens if You Fail an Inspection?

If your truck or driver fails inspection, you may be issued:

• A citation
• A vehicle inspection report (VIR)
• Out-of-service (OOS) status

An OOS order is serious—it means your vehicle or driver cannot continue until the issue is resolved. For example, a brake chamber leak or non-functioning service brake could trigger this status immediately.

Beyond the road, these violations are reported to the FMCSA and reflected in your CSA (Compliance, Safety, Accountability) score, which affects insurance rates, audit risk, and even contract eligibility.

Tips for a Smooth Inspection Experience

• Stay professional and courteous with the inspector.
• Never argue roadside—take note of the violation and appeal later if needed.
• Keep a clean and well-maintained cab—yes, cleanliness makes an impression.
• Review driver training on proper pre-trip inspections and documentation handling.
• Schedule 90-day preventive inspections, especially if you operate under BIT-like programs or state-level equivalents.

Make Every Inspection Count

DOT inspections are not just regulatory hoops—they’re vital checkpoints for ensuring road safety. By understanding the levels of inspection, preparing proper documentation, and staying on top of mechanical upkeep, fleets and drivers can sail through inspections with minimal disruption.

If you require a DOT inspection in Des Moines, IA, contact Kustom Truck & Tire today.