I would just ask both of them to correct their errors in driving habits. I'm sorry, but a $5 fine isn't worth hurting or killing someone. I doubt either driver has realized that, so maybe you can point that out. If they don't correct their driving habits, then I'd just complain to your local law enforcement and they should handle the problem quickly. Most law enforcement officers that I work with have a personal zero tolerance policy for speeding and reckless driving in a school zone, residential area, or any other high pedestrian/cyclist areas of similarity.

-Nate