Three things:

1. Discipline
2. Enforcement
3. Social courtesy

Once you get those three in line with each other, any infrastructure you modify, add, reduce, or impose on drivers will find their own place. Unfortunately, discipline and enforcement are the two key problems that are deeply rooted in our society not just in vehicular traffic but in other areas as well. Social courtesy basically becomes an annoyance once it's abused at the expense of others, and most often leads to lack of discipline (or vice versa), which the lack of enforcement cannot mend.