> A slight increase in average speed really only makes a significant difference over long drives.

Yes! I feel like I can't shout this loud enough. In addition to maintaining a safe driving distance, just leave a little earlier. The stuff I've seen people do in order to save 20 seconds boggles the mind.

Unfortunately, I think commuters fall into a gamification mindset. They're trying to set a new lap record each day, and you can see the results just by driving (or walking) during rush hour...