DOT Inspections | What to Expect
DOT Inspections | What to Expect -

DOT Inspections | What to Expect

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Are you serious about a career in the trucking industry? If so, you’ll need to familiarize yourself with the Department of Transportation (DOT). In this blog, we’ll break down the six levels of a DOT inspection and cover any necessary regulations and requirements you’ll need to know about. Continue reading for your ultimate guide to DOT inspections!DOT inspections

Commercial Motor Vehicle (CMV) Sizes and Weights

To begin, we’re going to cover the Federal Highway Administration’s (FHWA) size and weight regulations for commercial vehicles. These rules are put in place to maintain the safety of all vehicles traveling on the interstate highway system. 

Federal Size Regulations


The maximum width of a commercial motor vehicle allowed on the interstate highway system increased from 96 inches to 102 inches in 1982. This figure does not include mirrors and certain safety devices attached to the vehicle. However, Hawaii is the only exception to this rule. In this state, the maximum width allowed is 108 inches. If another state wishes to allow a greater maximum width, it must issue an over-width permit. 


Each state must follow certain minimum length requirements. The federal minimum for semitrailers is 48 feet or whatever the grandfathered limit is for a particular state. To give you an example, the grandfathered minimum length in Kentucky is 53 feet, while in Texas the grandfathered minimum is 59 feet. 


When it comes to height, states are allowed to enforce their own restrictions. These state height limits range from 13 to 14 feet, but there are some exceptions granted for lower clearance roads.

Federal Weight Regulations

The maximum weight allowed on the interstate highway system is 80,000 pounds. These rules also require that the maximum weight is 20,000 pounds for a single axle vehicle and 34,000 for a tandem axle vehicle. It is the responsibility of the state, not the FHWA, to handle overweight permits. These permits can only be issued if a vehicle load cannot be separated into smaller parts due to scheduling or safety issues.

Congress passed the Bridge Formula in 1975, which calculated the limitations on the weight-to-length ratio of a vehicle driving over a bridge. Axle spacing is an important figure in the bridge formula because a rig towing another vehicle adds more pressure to a bridge structure than a single vehicle does. The federal law notes that two or more consecutive axles cannot surpass the weight calculated by the bridge formula even if single axles, tandem axles, and gross weights meet the limits. 

DOT Inspections

Every commercial motor vehicle weighing over 10,000 pounds must pass annual DOT inspections. These inspections are very important because they guarantee that all commercial vehicles and their parts are in working condition. 

Below we’ll cover the six primary levels of DOT inspections. Remember that a DOT inspector or a state police officer can conduct these examinations anywhere.

Level I: North American Standard Inspection 

During this inspection level, an inspector will thoroughly check your documents and look for any drugs, alcohol, or hazardous materials in your vehicle. 

The items they will inspect are:

  • Driver’s license
  • Driver and Vehicle Inspection Report
  • Driver’s daily log and hours of service
  • Medical card and waiver 
  • Alcohol and/or drugs
  • Hazmat requirements
  • Seatbelt
  • Brakes 
  • Brake lamps
  • Headlamps
  • Stop lamps
  • Tail lamps
  • Turn signals
  • Lamps on projecting loads
  • Coupling devices
  • Exhaust system
  • Fuel system
  • Frame
  • Steering mechanism
  • Wheels, rims, and hubcaps
  • Windshield wipers
  • Suspension
  • Trailer bodies
  • Safe loading
  • Securement of cargo

Level II: Walk-Around Driver and Vehicle Inspection

The second level is almost exactly the same as the first level of inspection. But the key difference is that the inspector will only check the items listed above that do not require them to physically get under the vehicle.

Level III: Driver-Only Inspection

While conducting the third level of inspection, the official will examine the following items:

  • Driver’s license
  • Medical card and waiver
  • Driver’s log
  • Driver and Vehicle Inspection Report
  • Driver incident history
  • Hazmat requirements
  • Seatbelt

Level IV: Special Inspection

This level of inspection is only conducted once. It is used to examine an isolated part or feature of the vehicle. To clarify, a Level IV inspection is usually done to verify or refute a suspected trend found in the DOT’s inspection research.

Level V: Vehicle-Only Inspection

A Level V inspection can be carried out anywhere and includes every item in a Level I inspector which regards the vehicle. Also, the driver is not present during this examination.

Level VI: Enhanced NAS Inspection for Radioactive Shipments

All commercial vehicles carrying radioactive material must pass the North American Standard Level VI Inspection. The following list includes the items that will be examined:

  • Enhancements to Level I inspection
  • Inspection for radiological shipments
  • Radiological requirements
  • Enhanced out of service criteria

Preparing for DOT Inspections

Now that you know the different levels of a DOT inspection, it’s time to go over preparation. Additionally, it’s important to note that defective vehicles pose a serious threat to everyone on the road. To ensure your vehicle is functioning properly, you should do your own walk-around inspection before and after every trip you take. This inspection should include:

  • Checking your tires
    • Know your tire pressure and be aware of state regulations for mudflaps
  • Testing your lights
    • Faulty lights and signals should be replaced
      • Check headlights and high/low beams
  • Looking for damage
    • Even small cracks should be reported to prevent worse damage

Let us know if you have any questions or advice about DOT inspections in the comments below!

Author: Hit The Road Jack

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