There have been some recent changes in laws governing large trucks and trailers. There are certain circumstances that may require a commercial drivers license or an electronic logging device. If you have a large rig and drive long distances, more information can be obtained from the following locations.
https://www.horsecouncil.org/eld-mandate-cdl-requirements/
Federal Motor Carrier Safety Administration’s (FMCSA) Fallon Federal Building 31 Hopkins Plaza, Suite 800 Baltimore, MD 21201 Phone: (443) 703-2240 Fax: (443) 703-2253