I found this page, with a variety of short articles dealing with city traffic congestion, design ideas for vehicles and what a few cities (including NYC) are trying to do about it.
I particularly like the article on something called 'roundabouts'. Talk about saving fuel, and preventing accidents (about 80%)? About 150 to 250 circles are being built a year, in major metropolitan areas.
http://images.google.com/imgres?imgurl=h...