Rumbling through Illinois and Indiana are all sorts of big commercial trucks, hauling cargo to all parts of the country through our “Crossroads of America.” Our large truck traffic volume is much greater than in most states, and comes with an increased risk of a serious or deadly truck crash. Read, Semi Trucks and Big Rigs: High Indiana and Illinois Commercial Truck Traffic Creates Dangerous Conditions.
Trucks: Tractors and Trailers
For many people, it is simply a matter of daily life to deal with all these huge and heavy big rigs moving through alongside our sedans, SUVs, pickups, or minivans. Especially on our interstates (think I-294 in Chicago or I-65 and I-70 in Indianapolis), 18-wheelers are sharing our roadways with us at all times of the day and night. We may not take the time to consider how complex these vehicles are, at least until there is a scary problem with the big rig alongside or in front of us. Consider the following:
Within the commercial trucking industry, these motor vehicles are considered as a kind of motorized system, made up of the front unit with the big engine (the tractor) and the unit holding the cargo itself (the trailer). These two units may not be owned by the same individual or company.
They may be repaired, inspected, or maintained by different legal entities, too. And they may have entirely separate insurance policies (with varied requirements and exclusions) that come into play in the event of an accident.
The Tractor
The tractor is the motorized unit, where the truck driver operates the rig. It may include a sleeping compartment, as well as conveniences like small refrigerators; microwaves; TVs; and the like. The engine is extremely powerful, and built to pull the massive weight of the load inside the trailer hitched to it.
Tractors can be owned by motor carriers, fleet companies, or independent owner-operators. They will have their own VIN (vehicle identification number); their own license plate; and their own identification number filed with the U.S. Department of Transportation.
The tractors are operated by the trucker inside their cabin using controls (steering, brakes, etc.). Their engines can have 400 to 600 horsepower (HP), with some of the biggest semi-trucks achieving over 700 HP. Read, “Here Are The 10 Most Powerful Semi Trucks On The Road—And What Makes Them Mighty,” written by Asher Wyatt and published by Cars and Horsepower on May 12, 2026.
The Trailer
The attached unit, the trailer, holds the cargo. It does not have an engine. Trailers come in various designs and sizes, to accommodate various types of products and goods that will be transported by the tractor.
There can be intermodal trailers (think shipping containers); dry vans; refrigerated trailers (reefers); tankers; flatbeds; and more. Read, “20 Types of Semi-Trailers: A Comprehensive Guide,” published by Freightcourse (includes images of each type).
How Tractors and Trailers Work Together
Legally, there are different relationships between those in possession, custody, and control of the tractor and the trailer. A key factor here is who retains control over the equipment as it is being hauled along our roadways.
For instance, there are 18-wheelers on the Illinois and Indiana roads right now that are part of a carrier-owned fleet. Here, a trucking company owns both the tractor and the trailer and keep total control. That company also bears major duties of safety and care regarding both units.
Some big rigs here are hauls where an independent driver is operating a tractor that they own as an “owner-operator” but they have entered into a lease agreement with a motor carrier for their vehicle. They contract to provide driving services, pulling the carrier’s trailers (which will usually have the carrier’s logo or brand).
Other arrangements include interchange contracts, where the trucker drops off a loaded trailer at a hub, picks up another trailer owned by an entirely different company, and continues driving to deliver that load. There are also things like logistics brokers, who contract with a trucker to use their tractor to pull a shipper’s trailer to a destination.
Liability Gets Complicated When Trailer Caused the Truck Crash
In the event that a trailer is determined to have caused an accident, these legalities in the relationship between the tractor and the trailer can become a spider web of fault. Both accident reconstruction experts and legal advocates working for the truck crash victims will have to investigate the details to find what parties may have legal liability under state law.
1. Trailer Owner
For instance, the owner of the trailer may be liable if it is found that the trailer was improperly inspected, maintained, or repaired. Serious accidents can be the result of a trailer that had worn out brake drums, or a cracked hitch. See, 49 CFR Part 396 (Inspection, Repair, and Maintenance).
2. Carrier
The motor carrier may have legal liability if the truck driver failed to inspect things before driving off after the trailer was attached to the tractor. The trucker is required to do pre-trip inspections of the hookup. See, 49 CFR Part 392.7 (Pre-Trip Inspections).
3. Shipper
Finally, the shipper of the cargo held in the trailer may be at fault. If the cargo was not loaded correctly, there can be a shift or movement inside the trailer that can cause a tip over or rollover of the rig. See, 49 CFR Part 393.100 (Applicability and general requirements of cargo securement standards).
4. Design, Manufacture, Distribution, Sale, Repair, Maintenance of Trailer Part
There can also be liability for those involved in the design, manufacture, distribution, sale, maintenance and repair of the trailer. Flaws or failures in things like trailer brakes or breakaway systems or coupling devices can be devastating in a truck accident, and several third parties (from the designer to the company contracted to do repairs on the trailer) may be legally culpable. See, 49 CFR Part 393 (Parts and Accessories Necessary For Safe Operation).
Alsu read: Semi Truck Crash Liability: Third Party Liability in Indiana Truck Accidents.
Truck Crash Victim Injury Claims: FMCSA Regulations and Industrial Standards for Trailers
After a serious semi-truck accident, when investigations determine that the reason for the crash involved the trailer on the rig, there will be legal considerations of both the applicable federal regulations, as overseen by the Federal Motor Carrier Safety Administration, as well as various industrial standards developed to define and promote safety within the trucking industry.
For instance, in addition the above-referenced CFR cited regulations, there are promulgations that may be relevant from places like the Society of Automotive Engineers (see SAE J700 & SAE J133 regarding hitches, etc.) and the American Trucking Association (see TMC RP 708).
These trailer safety measures, if violated or disrespected, can form the basis of legal claims for those hurt or killed in the semi-truck crash. Claims independent of any worker’s compensation claim may be available to the trucker as well as to passengers and drivers of passenger vehicles hurt in the 18-wheeler accident.
For more:
- Expanded Semi-Truck Crash Liability: SCOTUS Rules Freight Brokers Are Liable for Negligent Choices in Transporting Goods
- Semi-Truck Crash: Evidence To Prove Injury Claims Using The Rig’s Electronic Logging Device (ELD)
- Chicago Semi-Truck Crash: Common Causes, Greater Danger of Truck Accidents in Chicagoland
- Deadly Truck Crashes and Truckers: Commercial Truck Drivers’ Licenses and FMCSA Oversight
- Truck Crash Injury Claim Evidence: ELDs, EDRs, and FMCSA Regulations to Show Liability.
Trailers and tractors work together to move cargo through Illinois and Indiana, with a surprising number of individuals and companies being involved in making sure those rigs are safe for both the trucker and those sharing the road with the semi-truck. Our part of the country has a greater volume of commercial truck traffic, and therefore we all face a higher risk of being involved in a serious truck crash. Please be careful out there!
