Police departments rountinely receive complaints from the public about trucks. Many times the truck is doing nothing wrong other than being a “truck”…the complaint stems from a lack of industry knowledge. Sometimes the complaint is about speed or lane use. Sometimes they complain about sand blowing off the truck and landing on their car. Other times it’s because the truck is throwing mud, slush, or ground water without splash guards (aka “mud flaps”). What most people don’t understand is not all trucks are required to have mud flaps…but the lack of understanding has nothing to do with mud flaps at all.
The first point of misunderstanding is that mud flaps are governed under state law, not federal law. The Illinois Vehicle Code (IVC) addresses this issue in 625 ILCS 5/12-710 There are nearly 600 pages in the print copy of the Federal Motor Carrier Safety Regulations, and zero regulations which require the use of splash guards. In 2006, the National Truck Equipment Association released a document listing the different mud flap requirements in all 50 states…and the variations are staggering. Given the political power of interstate trucking associations, it seems odd there is not federal oversight of a relatively minor equipment issue.
The second point of misunderstanding revolves around definitions of configurations. Every commodity being hauled on trucks or trailers has unique characteristics. Even with all these variations, there are still only a few categories to which all vehicles must fit:
TR = Straight Truck | Part 398.1(f) & 625 ILCS 5/1-211 TT = Truck Tractor | Part 398.1(g) & 625 ILCS 5/1-212 ST = Semi Trailer | Part 398.1(h) & 625 ILCS 5/1-187 PT = Pole Trailer | Part 571.3 & 625 ILCS 5/1-161 FT = Full Trailer | Part 571.3 & 625 ILCS 5/1-209 DC = Dolly Connector (Converter Dolly) | Part 393.5 & 625 ILCS 5/1-112.3
In Illinois, the IVC states: “It is unlawful for any person to operate any vehicle of the second division, except a truck tractor, to which this Section is applicable upon any highway of this State unless such vehicle is equipped with rear fender splash guards…”
The IVC continues to explain specific splash guard requirements, but basically all trucks are required to have mud flaps in Illinois except truck tractors…the definition is simple. Most police officers and truckers refer to truck tractors generically as “semi’s”, but it is important to understand why truck tractors are defined the way they are: “Every motor vehicle designed and used primarily for drawing other vehicles and not so constructed as to carry a load other than a part of the weight of the vehicle and load so drawn.”
Truck tractors have 5th wheel assemblies designed to tow semi-trailers (TT/ST). In this configuration, the power unit is carrying part of the trailer weight and its load. Compare that configuration to a straight truck towing a full trailer (TR/FT) behind on a hitch or pintle hook. In reality, there is some tongue weight being transferred to the straight truck from the full trailer, but that is not the design.
All of that to say this: truck tractors are exempt from splash guards in Illinois. One can argue that while in combination a semi trailer will knock down splashing from the tires of the truck tractor, but if the tractor is bob-tailing, is it really going to splash any less than a straight truck?
The answer is no, but the law is the law. Until the day the General Assembly decides otherwise, trucking companies need not put splash guards on their truck tractors. It does not matter if the vehicle is bob-tailing or in combination. However, the motoring public will probably love the truckers a little more if they do.