For my idea i would like to create bumper stickers that say something like: if you can read this you're too close! (that will be in small letters, so only the people who are actually too close can read it.) A safe distance is always a car length behind. That way not only does the driver reading the bumper sticker know that he is too close he also now knows the safe distance to drive and/or drive behind another car in order to help prevent bumper to bumper accidents, that can be easily prevented. My friend is my inspiration for this idea.