Quote Originally Posted by OC Richard View Post
I've watched a couple videos on roundabouts in the US.

The bottom line is that study after study has proven that they vastly decrease accidents. At least one study showed that they decreased fatal accidents by 90%.

For people outwith the USA, note that the vast majority of accidents here occur at intersections, and the vast majority of those are cars making left turns.

Numerous cockamamy intersection designs have been created to avoid having cars make left turns. Here's a type I experienced in Utah, called the "diverging diamond" https://www.youtube.com/watch?v=JnjqAwtkEkM

The simplest, most effective, and most obvious solution is roundabouts but Americans resist them simply because they're different.
IL uses a variation on the diverging diamond theme on some local road / highway interchanges.

Another way to avoid left turns are the "jug handles" they use in New Jersey. "Left turns" are made by going thru the intersection and having a loop to right which brings you to the street you crossed pointing the way a left turn would have gone. A little weird the first time but easy to get used to.