What’s the purpose of the project?

How did MoDOT choose the DDI?

Are there other DDI’s?

Will the Interchange be closed during construction?

What’s the construction schedule?

Q. What’s the purpose of the project?
A.  The purpose of this project is to provide safety improvements at the northbound and southbound exits from I-435, within the Interchange on Front Street and the entrance ramp onto southbound I-435. 

Q. How did MoDOT choose the DDI?
A.  MoDOT reviewed several preliminary designs for the I-435/Front Street Interchange, including a tight urban diamond interchange (TUDI), before deciding to move forward with the DDI.  Other designs had limited lifespans, low service levels, more conflict points, issues managing peak hour truck traffic, and more.  However, the Diverging Diamond Interchange offers a number of benefits including: 

• Improved safety
• Fewer conflict points
• Higher levels of service
• Better sight distance
• Reduced speeds
• U-turn accommodation
• Simpler signal timing and geometry
• Traffic-calming features
• More difficult wrong way entry onto ramps
• Less infrastructure to construct, maintain, and replace
• 50% lower overall project costs compared to the TUDI design
• More room for trucks to maneuver around the Interchange
• Shorter construction schedule
  
  

Q. Are there other DDI’s? 
A.  The first and only other DDI in the world is in Versailles, France.  Other DDI’s are currently under study at the Ontario Ministry of Transportation, the Oregon, Virginia, and New Mexico Departments of Transportation, and the City of Baltimore, Maryland. 

Q. Will the Interchange be closed during construction?
A. No, it will be open during construction.  Specific information about what’s happening during that time will be available on the 7-Day Outlook. The Outlook will describe what drivers can expect during Interchange construction, such as lane closures and traffic shifts, on a daily basis. General TDM strategies and maps of recommended alternate routes will also be included.   

Q. What’s the construction schedule?
A. Construction was anticipated to begin in spring 2008. However, construction of the I-435/Front Street DDI will be postponed until there is an opportunity to construct it without affecting traffic flow on the I-29/35 corridor. MoDOT is committed to not disrupting traffic flow at I-435/Front Street and I-35/Front Street at the same time. MoDOT is also managing the Chouteau Bridge project for the City of Kansas City, Missouri in coordination with the Department’s other projects. Construction of the I-435/Front Street Interchange should last one construction season. Some of the construction will likely occur at night and on weekends in order to avoid rush hour traffic.