Some of the easiest things to catch during a driver inspection are also the most common violations written up on a roadside inspection.
Proper pre and post-trip inspections should take at least 30 minutes to perform thoroughly and will reduce vehicle maintenance and violation costs.
This guide was developed based on what DOT inspectors look for at roadside and what maintenance often look for before releasing a vehicle. We will focus on the major sections and important details a driver should inspect, including the:
- Front of the vehicle
- Wheels and axles
- Lights, tires, leaks, and brakes
- Side of the truck and trailer
Front of the vehicle
Drivers should look for any intersecting cracks or large rock chips on the windshield, especially in the driver’s line of sight.
Honking the horn, whether that is the air horn or steering wheel city-horn, and turning on the windshield wiper is a simple step to make sure they are working properly.
Then, turn on all lights, which include the three marker lights at the top of the cab, clearance lights, and headlights. Test your high-beams, turn signals, and four-way flashers.
Open the hood and look for any obvious defects.
An easy part for DOT inspectors to check is the pitman arm and steering linkage. If there is any amount of play or looseness where the two gears of the pitman arm meet, it is considered an out-of-service violation and drivers will have to park until it is fixed. Sometimes, if rust is appearing here, it is a good indication that it is not tight.
Finally, check the suspension components. If it looks like your vehicle is leaning to one side, it is a good indicator that there is something wrong with the suspension components.
Wheels and axles
For wheels, check for cracks and loose or missing lug-nuts or wheel fasteners, and look for leaking hub grease.
It is an out-of-service violation for lug-nuts when:
- 10-lug wheels: 3 are missing anywhere or 2 adjacent to each other, or
- 8-lug wheels: 2 are missing anywhere
The steer axle is at the front of the power unit and has specific criteria that is different than other axles.
For example, to be in compliance, your required tire tread depth of a steer axle is higher compared to other axles, which are 4/32” depth and, 2/32” depth, respectively.
After the steer axle, we will move back to the drive axles. The first set of drive axles are either a single axle or group of axles that provide power to help move the truck down the road.
Trailer axles are at the back of the trailer. Some of these axles have sliding or tandem axles to help distribute the weight, to stay within regulations of maximum weight for a tandem axle.
If you are adjusting weight by sliding the tandem axles, you want to slide the axles toward the over-weight location. For example, if you are overweight at the rear of the trailer, then sliding the tandem axles further to the rear will help distribute the weight to the forward drive axles.
Tandem axles have notches on each axle. Each notch moves about 250 to 300 pounds to the other group of axles. Drivers may show up at a weigh station and find that they are more overweight then they were before, and that is because they are sliding the axles the wrong direction.
Lights, tires, leaks, and brakes
The three areas that most violations come from are lights, tires, and brakes. For example, low tread depth, damaged sidewalls, and inoperable light are easily visible and usually do not wear out on one trip.
It is important to check for flat or underinflated tires, fluids leaking, that all required lights are working properly, measure brake pushrod travel distance, brake pad thickness, and check brake can, hoses, and rotor surfaces.
It is an out-of-service violation for tires if:
- Underinflated tires are 50% or less of the sidewall rating
- There is a noticeable leak heard or felt in a tire
- The sidewall is cut, worn, or damaged
- There is a visual bump or bulge on any part of the tire, and
- If there is exposed belt or cord material
Leaks can come from the fuel tank, so make sure that it is securely mounted, and the fuel cap is the proper cap and is tight. Sometimes the cap is missing after fueling the truck because the driver forgot to put it back on. Be sure to check reefer trailers and auxiliary power unit tanks as well.
Side of the truck and trailer
Make sure that the air and electric lines are not lying on the deck area. The lines will rub while driving and eventually wear a hole in the lines, causing an air leak and the brake system to not work properly or even failing.
For 5th wheel assembly, make sure all components are secure, there are no cracks or damaged parts, and bolt tightness. Also, check for any rust driplines by the bolts. Rust will eventually cause bolts to be loose.
On the trailer, check for any damage on the trailer, trailer lights are working, any cargo securement devices are properly placed and tightened, and that there is a spare tire and tire chains secured properly.
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