Yellow Light Delay
Have you ever entered an intersection on a yellow light and then had traffic in front of you slow down so you couldn't get through before it turned red? Of course this is a rarity and yet at some time we all freak out and stress (as if driving isn't already stressful enough!) My idea is to have a traffic sensor that knows you're still in the intersection and delays the cross traffic green until you get out. Anyone entering on a red should still get a ticket but at least pedestrians and other traffic will be safeguarded against a possible tragedy. Such a smart intersection would likely only be used in a few places.
Reward: Safer roads