VIDEO: How Diverging Diamond Interchanges Work

In an attempt to reduce both crashes and traffic congestion, more states are constructing diverging diamond interchanges. But this interchange configuration is still rare enough to leave some drivers a little confused.

That’s why several states, including Florida and Wisconsin, have recently scheduled events aimed at familiarizing the driving public with how diverging diamond interchanges work.

So what are diverging diamond interchanges, or DDIs?

They are typically found at intersections located under or above freeway bridges. They direct traffic to briefly cross over to the left, or opposite, side of the roadway so that vehicles can turn left onto freeway on-ramps without stopping and without conflicting with through traffic. Traffic moves through the intersection and then switches back to the right side of the roadway.

Diverging diamond interchanges help move traffic more efficiently and safely than traditional intersections, studies show. They dramatically cut the number of conflict points at which vehicles can collide. DDIs also make wrong-way entry onto freeway ramps much less likely.

The best way to understand how DDIs work is to see how they work. To view a video from the Washington State Department of Transportation, click on the photo or link below the headline.