The busy interchange of SR 1 and Delaware SR 72 connects two important transportation corridors in the State. Since the interchange opened in the late 1990s, traffic has grown significantly along both corridors. Within the last 10 years, SR 72 traffic expanded from an average daily volume of 9,000 vehicles to almost 24,000, and SR 1 from around 67,000 vehicles to 90,000. Left turns were also becoming a problem.
After studying solutions to better manage this traffic growth, DelDOT decided on a diverging diamond interchange (DDI), as it would increase capacity of turning movements by allowing for “free-flowing, high-volume” left turns, while also reducing driver delays via two-phase traffic signals that provide more “green light time” on SR 72. Those two efforts not only improved safety for drivers by reducing number of conflict points, but also for pedestrians and bicyclists as well due to a new “shared-use” path. DelDOT said implementation of the $9.3 million DDI reduced travel times for vehicles by three to seven minutes, while making commuting safer and easier.