Oklahoma Department of Transportation – I-40 Elk City DDI

Drivers at the I-40 and SH-6 interchange consistently suffered from congestion and safety issues with the interstate off-ramps both situated on uphill grades and lacking traffic signals at the intersection points. With full support from the City of Elk City, the Oklahoma Department of Transportation designed and constructed the state’s first Diverging Diamond Interchange or DDI at this junction, with the benefits to drivers and from an operational perspective are already clear less than a year later. The new $16 million interchange easily handles the considerable amount of turning truck traffic that the non-signalized intersections could not handle. That truck traffic now interacts safely with passenger vehicle traffic, alleviating formerly frequent crashes and daily traffic tie-ups. Using an innovative interchange design like the DDI gives traffic direct turning motions to the north and south as it exits the interstate, reducing conflict points and congestion.