The Arizona Department of Transportation is planning to build another new type of freeway interchange designed to improve traffic flow and safety.

The interchanges would replace the roundabouts at Interstate 17 and Happy Valley Road, Houghton Road east of downtown Tucson and at two South Mountain Freeway interchanges.

So what is a Diverging Diamond Interchange?

In a diverging diamond interchange, local street traffic makes a temporary shift to the left side while crossing the freeway, allowing for direct left turns onto entrance ramps without waiting at an additional traffic signal.  The interchanges take some getting used to, as it can feel as though you’re driving on the wrong side of the road. (Anybody else think this is a bad idea in Arizona?)

More than 80 diverging diamond interchanges have been built in 29 states since 2009