The selected design proposes reconstruction of the I-35 and SH-9 West interchange as a Diverging Diamond Interchange with an additional reliever ramp to N.W. 12th Avenue. The DDI option, Alternative 2B, was the preferred choice of the Town of Goldsby and the City of Newcastle while also providing the best outcome for users of this interchange.
This design will help alleviate traffic backups on southbound I-35 during peak travel times and provides access to both SH-9 West and the local road system. Additionally, S. Harvey Street and N.W. 12th Avenue will be realigned to connect to the intersection of Bankers Avenue and Lamar Road, west of I-35. The preferred design, Alternative 2B, was selected from four proposals presented for consideration.
The innovative DDI design can accommodate large volumes of turning traffic by shifting traffic to the left side of a divided roadway through a series of coordinated signals for safer and more efficient left turns. Oklahoma’s first DDI at I-40 and SH-6 in Elk City opened in 2020 and has received many accolades, including national awards for quality bridge and pavement construction.
The department hosted a public meeting about this project in Goldsby and received written comments from more than 50 individuals and stakeholder organizations.
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During evaluation of the various design concepts and feedback from the public and stakeholders, ODOT determined the DDI is the best design for managing current and future traffic volumes on I-35 and SH-9 West as rapid growth and development continue in this area. I-35 currently carries nearly 82,000 vehicles per day in this area, and traffic volumes are projected to grow to 128,000 vehicles per day by 2050.
The estimated $20-million interchange reconstruction project is currently scheduled in ODOT’s Eight-Year Construction Work Plan to go to bid in 2023.
