The idea behind this law is that people do not run an unlicensed and unauthorized business fixing cars out of their residence. Imagine you live in a nice neighborhood, and your next door neighbor is running impact wrench, air compressor, and is being generally loud all day. That doesn't sound like a good living environment to me, and I can see why the law was written in the way that it was. Is it restrictive to an average car enthusiast, sure. But there is no way to write this law in any other form, without leaving a ton of loopholes. Big chances are, if you are working on your car in your garage time to time without causing too much noise, no one will ever report you for it, and you will never hear from the law enforcement to begin with. After all, Police Officers have something called discretion, which they mostly use to assess the situation, and see what's appropriate action.