I-75 / Fruitville Road Interchange
What is a Diverging Diamond Interchange (DDI)?
The Diverging Diamond Interchange (DDI), is a recognized design concept to improve traffic flow and reduce congestion. The purpose of this design is to accommodate left-turning movements onto arterials and limited-access highways while eliminating the need for left-turn bays and signal phases at the signalized ramp terminals. The highway is connected to the arterial cross street by two on-ramps and two off-ramps in a manner similar to a conventional diamond interchange. However, on the cross street, the traffic moves to the left side of the roadway between the ramp terminals. This allows the vehicles on the cross street that need to turn left onto the ramps to continue to the on-ramps without conflicting with the opposing through traffic.
What are the benefits of a DDI?
The DDI design provides a safety benefit because it reduces the number of potential conflict points through the elimination of potential crossing conflicts between vehicles turning left onto the freeway and opposing arterial traffic. Although traffic signals are used to separate conflicts between vehicles, and other roadway design features, such as signs and markings, are intended to reduce the probability of driver errors that may result in crashes, safety performance generally is better when the number of conflict points is minimized. Besides the potential safety benefits of the DDI, the design also offers operational and cost benefits over alternatives at grade-separated interchanges. In locations where the DDI has been implemented, construction costs are approximately half as much as a conventional diamond interchange retrofit because the additional turn lanes typically required during an interchange improvement would require widening the overpassing bridge. Furthermore, traffic modeling suggests that a DDI operates at a much higher level of service and capacity.
How does a Diverging Diamond Interchange (DDI) operate? Click on the link below to see an example of a DDI interchange currently being constructed at I-75 and University Parkway in Sarasota.
I-75 / University Parkway DDI video I-75/University Parkway
What is the current schedule for the I-75 / Fruitville Road Interchange design project?
|Construction:||Not currently funded|