At the HCI Lab (Stanford University), there is currently a research project about to discourage drivers from speeding. They put online the results of their brainstorm in the form of drawings which are amazingly interesting: If you want to know more about it, read: Dynamic Speedometer: Dashboard Redesign to Discourage Drivers from Speeding by Manu Kumar and Taemie Kim (CHI 2005).

For 'user experience' freaks, they also give access to their data here.