New Jersey Statutes Title 39. Motor Vehicles and Traffic Regulation 39 § 4-101

Nothing in this article shall apply to a speedway, constructed with the permission of the local authorities or the board of freeholders, as the case may be, of the county or counties in which the speedway is located, and built or intended for the exclusive use of motor vehicles, if the speedway at no point crosses a highway, railroad or railway at grade.