The preliminary design of a diverging diamond interchange for Interstate 75 and County Road 99 in Findlay, Hancock County. 

The Ohio Department of Transportation (ODOT) District 1, the city of Findlay, and the Hancock County Engineer’s Office have chosen a diverging diamond interchange (DDI) for the rehabilitation project at the Interstate 75 and County Road 99 interchange to combat growing congestion at the important economic hub.

The option was one of four presented to the public during a virtual public involvement meeting in August.

A DDI shifts the eastbound and westbound traffic to the other side of the bridge at signalized crossovers which eliminates left turns across traffic and the traffic signals for left turns.

The benefit is that all traffic can enter the interstate in a free flow movement to the ramps which reduces the long start and stop times of trucks at signals. A successful example of a DDI is located in Perrysburg at I-475 and SR 25.

“A DDI will ensure the sustainability of the economic opportunities in this corridor,” said County Engineer Doug Cade. “With increased commuter and truck traffic comes the need to take steps to improve the efficient movement of our labor force and goods to and from this area so that we can continue to see prosperity and be ready for future opportunities,” said Cade.

Another benefit of the DDI is improved safety through reduced conflict points. Compared to a conventional diamond interchange, the DDI reduces vehicle-to-vehicle conflict points by nearly 50% and eliminates many of the most severe crash types. 

The results of crash analysis at the I-75/CR 99 interchange conclude that the benefit-cost ratio of a DDI will have safety benefits that exceed the additional cost of construction.

The project will construct an additional bridge next to the existing bridge over I-75, to the south. The new structure will provide three westbound lanes. Additional improvements will be made along the CR 99 corridor, including the intersections with Technology Drive, Speedway Drive, and Ventura Drive.  

A shared-use path for bike and pedestrian traffic will be constructed along the south side of CR 99 and utilize the original bridge structure for crossing over I-75.

Construction funds are not yet secured for the project. Preparing the design will help the project move forward quickly once the funds are available. In the immediate future, crews will perform soil borings to begin the detailed design of the new interchange.

The completed feasibility study and other documents are available on the project webpage at www.transportation.ohio.gov/Hancock99