Are Diverging Diamond Interchanges The Roundabouts Of The Future?

There’s no question that Chicagoland has more than a few intersections that could use some tuning up to help traffic flow and prevent car accidents. The question is, what is the best way to fix them?

Over the years, more and more roundabouts have been popping up in Chicago and it’s suburbs, with one of the earliest appearing in South Holland back in 2008. Now they are fairly common, and new ones seem to appear every year. They are designed to slow traffic and prevent the most serious car wrecks such as T-bone accidents and head-on collisions, not necessarily to prevent wrecks altogether. However, some people still find them frustrating and challenging to navigate.

Now comes the diverging diamond interchange, sometimes referred to as a double crossover diamond interchange. Like roundabouts, these diamond shaped intersections are imports from Europe, where they first appeared in France in the 1970s. Modernized versions started being built in the United States in the early 2000s. Popular Science named them one of the best innovations in 2009. The diverging diamond interchange made its first Chicagoland appearance recently at the intersection of I-88 and Illinois Route 59 in Naperville, and there may be more on the way.

Diverging diamond interchanges differ from roundabouts in that they are meant for intersections between freeway and nonfreeway traffic. Like roundabouts, though, their design has created a great deal of initial confusion, thanks to the feature that requires drivers to drive on the wrong side of the road for a brief period of time.

While the interchange is meant to improve traffic flow as people enter and exit the expressway and minimize the risk of turning accidents,a news report indicates that car crashes actually increased at first, though the report does not indicate whether the crashes were minor or severe. Similar reports of increased crashes have been initially made about roundabouts, though evidence suggests that crashes that resulted in serious injuries or death declined as intended.

Time will tell how prominent these interchanges will become. While new traffic configurations can be confusing, if they result in fewer traffic injuries and deaths, then they are well worth it.