What ordinary people erroneously think of as safety and convenience. Light shining vertically contributes nothing to safety and convenience. Spill light shining horizontally that does not illuminate anything that needs to be illuminated is even worse, since 1) light that is nearly horizontal that passes through hundreds of miles of atmosphere before getting into space illuminates more dust particles and thus produces more skyglow than light shined vertically; and 2) horizontal light that shines directly into the eyes of passersby (e.g., motorists) produces glare that impairs their ability to see things they need to see (like pedestrians, animals and hazards).
People who are familiar with the subject matter understand that light trespass and glare reduce safety and convenience.
Ah. Experts.
Forget it.
You’ll never get through to this crowd.