As of April 4, 2023, all work was completed and this project was final-accepted from the contractor.
This project reconfigured the I-75 / SR 56 interchange between CR 54 and Cypress Ridge Boulevard in Pasco County. The former diamond interchange was modified and converted to a diverging diamond interchange (DDI). The main change was to diverge (cross) SR 56 traffic to the left side of the road through the interchange, and then cross vehicles back over to the right side of the road on the opposite side of the interchange. The improvements help alleviate traffic congestion at the interchange to reduce travel time for motorists in this rapidly growing area.
* Construction cost includes original construction contract amount plus approved contract changes. It does not include inspection oversite.
MAJOR PROJECT UPDATES
- The interchange of SR 56 and I-75 was converted to a Diverging Diamond Interchange traffic pattern on May 1, 2022.
- All lanes are open throughout the project area! A fourth westbound SR 56 lane was opened on October 31, 2022, along with a third left turn lane from the northbound I-275/I-75 exit ramp onto westbound SR 56.
- All pedestrian and bicycle facilities were open throughout the project area as of December 10, 2022. Pedestrians have 5-foot-wide sidewalks on each side of SR 56 and cross into a barrier-protected 7-foot-wide section in the median of the bridge over I-75. Bicycles have dedicated lanes next to traffic in each direction of SR 56.
Why convert the interchange to a DDI?
A DDI was chosen for the I-75 / SR 56 interchange because of the proven ability of this traffic configuration to increase safety and capacity while using a large amount of the existing interchange footprint, including the existing bridge. The DDI was also chosen because of its ability to handle heavy left turn volumes, such as the westbound to southbound movement from SR 56 to SB I-75.
The expected benefits for the interchange are an increase in capacity and pedestrian safety while reducing vehicle delays and crashes. These benefits will be achieved by an increased number of lanes, improved pedestrian facilities, more efficient signal timings and reduced vehicle conflict points.
How does the DDI work?
Unlike a conventional diamond interchange -- no matter what direction you are driving on State Road 56 – you diverge -- or cross to the left side of the road through the interchange, and then cross back over to the right side of the road, on the opposite side of the interchange.
The Diverging Diamond Interchange at State Road 56 reduces vehicle delays by allowing traffic to enter the interstate without waiting at a left turn signal. To do this, traffic is redirected from the right side of the bridge to the left side.
Signalized crossovers are positioned at each side of the interchange, and are designed to cross eastbound and westbound State Road 56 traffic with no turning movements at these two intersections. This design allows for more efficient signal timing, which reduces delay times, minimizes conflict points, and enables the interchange to more effectively handle higher volumes of traffic while eliminating the more serious crashes associated with a conventional interchange.
Other features and benefits of diverging diamond interchanges
- DDIs operate under two-phase signal control, which reduces lost time, delays and queue lengths at traffic signals.
- Safety features include lower design speeds between ramps and a reduction in the number of conflict points. The lower speeds result in less severe crashes.
- Increased safety for pedestrians and bicycles.
- Better sight distance at turns.
- There are no closures at this time.