Why make the rules complicated? So you can make more money from the lawless idiots! Of course!

Same reason for Red Light Cameras and Speed Cameras. Safety? Maybe as a side effect... but we need those monies to make up for budget shortfalls!!!

Throw in Business Hours, school zones, happy hour, etc...

Also... the US is stupidly enshrined in making everything against the law - and punishable with fines (or more)... For being the Land of the Free, we sure do love our laws...