Half-Diverging Diamond Interchanges Open On South Mountain Freeway

Valley commuters saw progress made on the South Mountain Freeway on Monday as two new “Half-Diverging Diamond Interchanges,” commonly known as DDIs, opened. ADOT opened the L-202 South Mountain Freeway interchanges at Desert Foothills Parkway and 17th Avenue.

The new interchange first moves drivers through a traffic light, allowing one direction to move at a time before shifting traffic to the left to enter the freeway.

The interchange eliminates left-turn arrows, allowing drivers to merge left without cutting across traffic.

According to the Arizona Department of Transportation, “DDIs are an innovative, proven solution to improve safety and mobility for motorists, cyclists and pedestrians.”

With the opening of the new area, drivers are using more freeway lanes in the area. However drivers need to pay attention to the posted speed limit. The area is still considered a work zone and the speed limit is 40 mph.

“Starting Monday and continuing until next summer, there will be no access to and from the future freeway at 32nd Street, which will close south of Liberty Lane for interchange ramp construction. Interchanges at 24th Street and 40th Street are alternate routes. Access to Pecos Storage will be maintained throughout construction,” stated ADOT officials.

There are two more diverging diamond interchanges planned in Arizona: one at the Interstate 17 and Happy Valley Road in 2020; the other is planned for Tucson.

Click here for more information on the South Mountain Freeway.