Elk City's Diverging Diamond Interchange at I-40 & SH-6
Coming soon: Oklahoma's first DDI
In 2015, the existing twin bridges on SH-6 over I-40 were deemed structurally deficient, meaning the roadway is safe for travel but in dire need of repair. Starting in mid-2019, ODOT will demolish the existing SH-6 bridges over I-40 and replace them with a new type of interchange - a Diverging Diamond Interchange.
Watch: A step-by-step video of how to use a Diverging Diamond Interchange
Watch: See what I-40 and SH-6 will look like once the DDI is completed
Courtesy: CEC Corporation
(Edit: Plans are to also place stop lights on the ramps.)
Elk City is a growing community. Sitting along the famous "Mother Road" Route 66, the town experiences high traffic volumes on both I-40 and SH-6. The last survey completed in 2017 shows 8,500 vehicles travel SH-6 on average per day.
About the Project
Construction of Oklahoma's first Diverging Diamond Interchange is scheduled to begin in September 2019 at I-40 and SH-6 in Elk City. The innovative design offers a proven solution for improving traffic flow and safety at the interchange.
- Reconstruct SH-6 and I-40 on-and-off-ramps.
- Construction is estimated to cost $15 million.
- Construction is scheduled to start in May 2019.
- Construction is expected to last about a year, with an completion date of May 2020.
About Diverging Diamond Interchanges
The definition of a Diverging Diamond Interchange: Two directions of traffic on the non-freeway road cross to the opposite sides of the bridge at the freeway.
- Currently, there are just under 100 DDIs nationwide.
- The first was constructed in Springfield, MO in 2009.
- DDIs create safer, less congested intersections.
- DDIs allow for fewer conflict (accident) points.
- DDIs give drivers better sight distance at turns.
- DDIs pedestrian crossings are shorter.
- DDIs aim to eliminate the left turn and thereby increase safety
- DDIs give "free-flowing" or simple left and right-hand turns from all directions.
- Wrong way entry to ramps become extremely difficult.
Traffic Impact During the Project
- I-40 and SH-6 will remain open to the traveling public.
- I-40 will be narrowed to one lane in each direction at times throughout the project.
- I-40 will have minimal ramp closures at SH-6.
- Crews will have minimal nighttime closures of I-40 and SH-6 to demolish the existing bridges.
During the project, drivers should use the following sources to stay connected about changing traffic conditions:
- ODOT's traffic advisories at http://ow.ly/3GMU30nwdjE
- ODOT's Twitter and Facebook accounts
- ODOT's app on the Apple App Store
Last Modified on 06/05/2019
The Oklahoma Department of Transportation (ODOT) ensures that no person or groups of persons shall, on the grounds of race, color, sex, religion, national origin, age, disability, retaliation or genetic information, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any and all programs, services, or activities administered by ODOT, its recipients, sub-recipients, and contractors. To request an accommodation please contact the ADA Coordinator at 405-521-4140 or the Oklahoma Relay Service at 1-800-722-0353.