Amends the Illinois Vehicle Code. Provides that local authorities with respect to highways under their jurisdiction may also, by ordinance or resolution, prohibit the operation of trucks or other commercial vehicles, or may impose limitations as the weight, height, or length (rather than only weight) thereof, which prohibitions and limitations shall be marked by appropriate signs placed on such highways. Establishes that an agency or instrumentality of the State of Illinois or any unit of local government shall not be required to widen or otherwise alter a non-designated highway (regardless of its date of construction) to accommodate truck-tractor-semitrailer combinations. Provides that each unit of local government may (rather than shall) report to the Department of Transportation any limitations prohibiting the operation of vehicles imposed by ordinance or resolution in the unit of local government's non-designated highway system. Makes conforming changes.