Optimizing for revenue collection is designing the rules to be easily broken. This does not enhance safety. If you want to bust a lot of speeders by a school,

Optimizing for revenue collection is designing the rules to be easily broken. This does not enhance safety. If you want to bust a lot of speeders by a school, you must first have a lot of people speeding by a school. The best way to do this is to have a nice, straight, uncontrolled road that's clearly safe to drive at a faster speed than posted. That will encourage speeding and thus ticket revenue when you set up a speed trap. If you are more concerned about the safety of children crossing the road, you will do things to discourage people from actually driving fast. You'd make the road curvy, make T-intersections 3-way stops, put in speed bumps, add crossing guards, or use whatever combination of a variety of techniques makes sense for that road in order to make drivers go slower.