PDFWAC 204-70-030
Scope.
(1) The scope of this regulation is directed to the regulation of trailer hitches and towing devices, towing methods, testing methods, certification requirements, installation, compliance and other requirements as herein defined in these regulations used for drawing a trailer or semitrailer having a gross vehicle weight of 10,000 pounds or less upon the public highways of this state.
(2) This regulation is not for those arrangements used for drawing another vehicle by means of a tow truck, semitrailer with a fifth wheel type hitch, or wrecker unless coupled by ball and coupler.