A Diverging Diamond Interchange (DDI) is an innovative way to improve safety and capacity. DDIs reduce the total number and severity of conflict points by eliminating left turns that cross opposing traffic. This strategy requires careful design of the crossover intersections to ensure they are intuitive to drivers to avoid confusion and bad decisions being made.
This presentation will focus on best practices for selecting, designing and implementing DDIs. Several aspects of DDI development will be discussed, including traffic operations , geometric design of the crossover intersections, cross slope and profile design, selection of appropriate design speeds, traffic signal placement, multimodal accommodations, and public outreach/education. This presentation will pull from numerous real-world DDI project examples across the country and showcase how these lessons were applied.