Wheel And Crawler Tractors 80 6. Buses 81 7. Snowmobiles 81 8. Federal regulation and federal preemption of state and local noise emission standards is required when the source of noise is a vehicle for interstate commerce or one of the categories of sources set out in the Noise Control Act. State regulation, however, has increased in recent years in order to control nontransportation noise as well as transportation noise when federal standards have not been promulgated or when noise can be controlled through licensing or other restrictions not preempted by the Act.
Local regulation fills in the remaining gaps, of which there are many.