How to prove overloaded truck caused accident evidence
Truck Accidents - August 12, 2026
The evidence that proves an overloaded truck caused an accident is mostly the truck’s own paperwork and data: scale tickets, weigh station records, the bill of lading (the shipping paperwork that lists what went on the trailer), and the electronic data commercial trucks store about speed and braking. The hard part is getting to those records before they’re gone, which is why a Chicago truck accident lawyer will usually send a preservation demand to the trucking company within days of a truck crash.
What counts as an overloaded truck under federal regulations?
On interstates, a truck exceeds the legal limit when its gross vehicle weight passes 80,000 pounds, or when a single axle carries more than 20,000 pounds or a tandem axle more than 34,000. Illinois uses the same numbers on state routes. Gross vehicle weight just means the truck, trailer, fuel, and freight added together.
A truck can also be improperly loaded without being overweight. Federal Motor Carrier Safety Administration rules say a truck driver can’t pull out unless the cargo is properly distributed and secured. Say a flatbed leaves an intermodal yard on the Southwest Side with steel coils sitting too far back on the trailer. It’s under 80,000 pounds, but the weight rides over the rear axles, and when the driver brakes hard on the Stevenson, the front tires don’t have enough load on them to steer. That truck is improperly loaded even though it’s under the limit, and the loading company can share the blame for it.
What evidence proves an overloaded truck caused the accident?
The strongest evidence is a weight measured close to the time of the crash. Police can weigh a truck after a crash, and when they do, that number lands in the crash report. Weigh station records and scale tickets from the shipper show whether the truck exceeded legal limits when it left. The bill of lading lists what was loaded, so a gap between the paperwork and the scale is one of the first things we look at.
Electronic data covers what the paperwork can’t. The engine control module, the truck’s onboard computer, records speed, throttle, brake use, and fault codes in the seconds before impact. The electronic logging device shows where the truck was and when, including whether it drove past an open weigh station on the interstate rather than pulling in. Witness statements matter too, especially from anyone who saw the trailer squatting or swaying before the crash occurred.
How does an overloaded truck cause a crash?
Extra weight changes how a truck stops and turns. Brakes are rated for a certain load, so an overweight truck needs more room to stop, and its brakes fade sooner. Tires have a load rating too, and weight past that rating is how blowouts happen. A high or uneven load raises the trailer’s center of gravity, which is what puts a truck on its side in a ramp curve.
In truck accident cases, a crash reconstruction engineer takes the weight, the electronic data, the skid marks, and the damage to both vehicles and works out whether a legally loaded truck would have stopped in time. Your medical records then connect your injuries to the force of that impact. Tractor-trailer crashes killed 106 people in Illinois in 2024, and 83 of them were riding in other vehicles.
Who is responsible when a crash involving an improperly loaded truck happens?
Usually more than one company is responsible. The driver is responsible for checking the load, and the carrier is responsible for its training and policies. The shipper or loading company answers for what actually went on the trailer, and the broker that arranged the haul may be responsible as well. We cover how those claims fit together in our post on third-party liability in truck accidents.
How fast does this evidence disappear?
Some of it is gone within months. Federal rules only require carriers to keep electronic logs for six months, and driver inspection reports for three, and the truck itself may be repaired and back on the road within weeks. A spoliation letter puts the carrier on notice that it has to preserve everything. A court can penalize a company that destroys records after receiving one, including by telling the jury to assume the missing records would have hurt the company’s case.
In Illinois, truck accident claims have to be filed within two years of the crash, and within one year if a city or other local government vehicle was involved.
Talk to a Chicago truck accident attorney at Horwitz, Horwitz & Associates
Horwitz, Horwitz & Associates has handled truck cases for decades, and our own third-party department pursues the shipper and loader alongside the carrier instead of referring that part of your case out. Your case won’t be pressured into a quick settlement. We work on a contingency fee basis, and you pay no attorney’s fees unless compensation is recovered.
Call (800) 985-1819 or contact us online for a free consultation.
