Unlike a conventional interchange, the lanes in a DDI cross over to the left side of the roadway. That limits the number of traffic signal phases and allows drivers to make a left turn without crossing in front of oncoming traffic. The lanes then change back to the right side of the road. Central Florida’s first DDI opened at Interstate 95 (I-95) and Viera Boulevard in July 2019.
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Right now, there are dozens of diverging diamond interchanges (DDIs) planned for the state of Florida, including several as part of the I-4 Beyond the Ultimate projects. The first DDI in Florida opened in 2017 at I‑75 and University Parkway on the Sarasota-Manatee county line, where it's one of the busiest in the U.S. Learn more about these innovative interchanges below.
The driver should proceed through the first traffic light, staying in the lane in which he or she is driving. The lane will guide the driver to the opposite side of the road. Before the lane crosses back to the right side of the road, the driver will encounter one more traffic signal.
If the driver wants to turn right onto a freeway ramp from the arterial road, the driver should use the right turn lane, just like in a conventional interchange.
When turning left onto a freeway ramp, the driver should stay in the left lane and follow the lane through the first traffic light on to the other side of the road. Then, before going through the second traffic light, the driver will turn left onto the freeway ramp.
Turning right onto the arterial road from a freeway ramp is as easy as taking a right turn at a conventional interchange. When turning right onto an arterial road, remember to yield to oncoming traffic and watch for pedestrians and bicyclists using marked walkways.
To turn left onto the arterial road, follow the left lane and, when traffic allows, take a left turn. The lanes will guide the driver from the left side of the road to the right side of the road, similar to going straight through the interchange.
Compared to walkways in conventional interchanges, pedestrian walkways are shorter in DDIs. When walking through a DDI, pedestrians should cross traffic on designated crosswalks to reach a median. They cross traffic again to reach the other side of the interchange.
Bicyclists traveling through a DDI can either stay in the bike lane or dismount and use pedestrian walkways.
Here are some things to keep in mind when approaching a DDI on a bicycle:
- Cyclists uncomfortable with riding through the DDI can walk their bike through the interchange on the pedestrian walkways as stated above.
- When riding alongside traffic, cyclists should remain in the bicycle lane by following the pavement markings.
- When automobile traffic shifts to the left side of the road, cyclists will be on the inside rather than the outside. The bike lane will shift back to the outside on the far side of the interchange when traffic returns to the right side of the roadway.
As part of I-4 Beyond the Ultimate projects, six additional DDIs are currently in design for the Interstate 4 (I-4) corridor in Osceola, Orange, Seminole and Volusia counties. Those will be located at the I-4 interchanges of County Road (C.R.) 532, Daryl Carter Parkway, Sand Lake Road (S.R. 482), Lake Mary Boulevard, C.R. 46A, and State Road (S.R.) 472.
Construction of the DDI at C.R. 532 began in summer 2021, while construction for the DDIs at Daryl Carter Parkway and Sand Lake Road is scheduled to begin in 2022 and 2023, respectively. These innovative interchange configurations have been shown to improve safety, increase traffic efficiency, and be cost-effective.