Everyday I ride to work on wide roads clearly marked with a 35 mph speed limit and everyday I'm passed by cars going between 45 and 55 mph. Speed kills, not only cyclist, but motorcyclists, pedestrians, and other drivers. If there's one thing that drivers could do to make cycling in Atlanta better it's simply to slow down. Ever since I started cycling as an adult I've noticed big changes in driving habits. I once suffered a severe case of lead footisness, now I never speed. And do you know what? I hardly miss the 3 extra minutes it takes me to get places.
Post Script: I really think the Cobb County Police Department deserves credit for their traffic enforcement efforts. I've often seen them running radar on one of the roads with the most egregious violators.