Not defending the people throwing trash but mixing automobiles and bicycles is a bad idea. Tucson considers itself bicycle friendly and has bicycle lanes. There are accidents at least once a week and the automobile always wins. Don't know the answer.
Serious question, what makes it a bad idea in your mind?
Tucson is indeed a bike friendly town with lots of bikes on the roads as well as non motorized bike trails, but if you watch the local news it's rare for a week to go by without at least one bicyclist fatality.
I'd be very surprised if Tuscon averaged one a month.
