A separate braking system is required for trailers over 3,000 pounds GVW in Illinois according to Road King. GVW is the weight of the trailer, plus the weight of any passengers and cargo. Edmunds recommends separate systems for any trailer over 2,000 lbs. gross trailer weight--the weight of the trailer alone.
Edmunds notes there are two common types of trailer braking systems. These are surge brakes, which operate hydraulically, and electric brakes, which are operated by a controller in the tow vehicle that responds to pressure on the brake pedal.
According to Edmunds, all trailers are required to have brake and tail lights. Trailers must be registered with the Department of Motor Vehicles in most states. In Illinois, trailers may not exceed a length of 60 feet, height of 13 feet 6 inches and a width of 102 inches.
