I've been trying out alternate routes around my neighborhood, looking for the least traveled streets, and the streets with traffic circles are definitely the motherlode!
Some neighborhoods in my area in an effort to calm traffic, have been installing traffic circles at every intersection along some residential routes that commutters were using as shortcuts between main thoroughfares. Boy, do they work! Cars hate them and avoid the routes like the plague.
On a bike, they are great. They parrallel very busy, dangerous streets for miles. No stop signs! And most are on narrow two lane streets which make it pretty hard to get around in a car, but its easy to fly around them on a bike.
Alright, I know its not that big a deal, but here in Miami, rode rage capital of the US two years in a row, little things like this give me hope.