A pet peeve of mine that they cannot even begin to regulate but likely wastes much more fuel is the idiots that feel that they have to floor it from stoplight to stoplight...

We have a stretch of road here with a series of stoplights that are actually in series as far as the controls go. If I slowly start off from the first light and come up to the posted limit, each light turns green as I approach it - which is what they intended. Of course, everyone around me is flooring it and then slamming on the brakes at the next intersection, waiting the few seconds for the light to turn green, flooring it, slamming on the brakes, flooring it...

Problem is that you cannot legislate intelligent driving just by posting speed limits...