Directed by the Noise Control Act of 1972 (42 USC4901...) to "promote an environment for all Americans free from noise that jeopardizes their health or welfare3-1," the recently created EPA and its Office of Noise Abatement and Control studied this noise problem in detail.
They looked at all sources of environmental noise and identified motorcycles and motorcycle exhaust systems as "major sources of environmental noise3-2." The EPA studied in detail the effects of noise from these major sources on people while at work, and at home while relaxing and sleeping. They examined several methods (including current states efforts at that time) to abate motorcycle noise, and created a national plan that utilizes local level police as enforcement to achieve this goal3-3.