There is an irrational double standard that applies to fixed installations such as factories. Noise created inside factories is sometimes limited by zoning laws, but mobile "factories" such as garbage trucks, fuel trucks that pump oil into homes, refrigerated trucks, are not covered by decibel limitations even though the noise they generate affects residential areas much more directly. "Objectionable industrial noise," reported the American Society of Planning Officials, designers of the performance standards for zoning codes, "is overwhelmingly due to traffic and transportation noises—trucks coming from and going to the plant, steam locomotives puffing and diesel engines thundering, box cars switching and gondolas banging, thousands of self-propelled employees changing shifts. The chance of controlling this type of noise through a performance standard on noise generation is not good." It is conceivable that a community zoning code would control the noise of rockets being built inside a factory, but would exempt the noise of rocket engine tests if the testing occurred outside the plant.
Zoning laws, in their failure to cover aircraft operations and construction noise, are indeed limited in effectiveness. "Mobile industries seem to consider themselves privileged as far as noise is concerned," complains Jim Botsford, who is Bethlehem Steel's Noise Control Engineer. "They argue they are vital to the economy and the public interest. [But they are] no more so than many industries fixed to real estate...There is no valid reason why local business should be required to 'shut up or shut down' at night while trucks and airplanes are allowed to roar through until dawn."