Dive Brief:

• The Florida DOT (FDOT) is planning a $2.3 billion rebuild of two, 20-mile sections of Interstate 4, an initiative that will connect to the western and eastern ends of the current I-4 Ultimate expansion project in Orlando and attempt to tame traffic around a busy Walt Disney World (WDW) entrance, according to Orlando Weekly.
• The eastern portion of the "I-4 Beyond the Ultimate" project, which will extend into Volusia county near Deltona, Florida, is not yet funded. However, the FDOT is proceeding with the western leg of the project, which will see a retail plaza and apartment complex near a WDW gateway razed to not only create a complex system of flyovers, bridges, exits, express lanes with variable toll pricing and interchanges, but an extensive drainage area in accordance with FDOT rules. When the western edge of the expansion is complete, the agency will have added 62 bridges and replaced 27 existing ones, as well as have created sidewalks along nearby county roads and other pedestrian-friendly upgrades.
• The FDOT said it wants to create a signature corridor to expand the area's safety, mobility and connectivity. Although each of the expansion's current six segments is in various stages of design and planning, including a land acquisition process that will take several years, the agency said it has completed the Development and Environment (PD&E) Reevaluation Study for the entire project.   

Dive Insight:

Beyond the Ultimate will be using a diverging diamond interchange (DDI) as part of the western end of the project. While possibly confusing to some at first, more DDI's are being used, particularly in Florida, which at the end of 2017, had almost 40 under construction or in development. This project alone boasts six.   

One of the DDI's most beneficial design features is also one that causes confusion for some at first, and that is the removal of virtually all left turns across traffic. Routing vehicles this way allows for a freer flow of traffic and minimizes the number of accidents. The first DDI in the U.S. was built in Springfield, Missouri, and in its first year of operation, Missouri Department of Transportation officials reported that total accidents on the DDI were down 46%, and left-turn crashes had decreased 72%. In addition, 80% of the motorists surveyed reported fewer delays.

DDI's are just one way of maximizing the driver experience through design. Other tools include the cloverleaf, diamond, single-point diamond and roundabouts, all of which are meant to ease congestion and improve the pace of traffic flow once drivers become accustomed to navigating them.