Drivers in the West Valley can now use the second I-10 Diverging Diamond Interchange (DDI) to be constructed as part of the Arizona Department of Transportation’s ongoing freeway widening project in the Buckeye area.

Crews reopened the I-10 interchange at Watson Road today (Thursday, April 27). The interchange has been reconstructed using the diverging diamond design, which has grown in popularity across the country for safety and traffic flow benefits.

Diverging diamonds allow the two directions of cross-street traffic traveling over or under a freeway to shift to the opposite side of the roadway. The crossing is designed to improve the overall movement of traffic and enhance safety by limiting potential traffic conflict points and allowing direct left turns onto a freeway entrance ramp. Drivers avoid waiting at a traffic signal and don’t cross in front of opposing traffic when making those left turns.

ADOT continues work to widen 8 miles of I-10 from two to three lanes in each direction between Verrado Way and State Route 85. The entire $82 million I-10 improvement project, which was launched in July 2021, is on schedule for completion this summer (2023).

The I-10/Watson Road interchange is the fourth full diverging diamond to be added along the state’s highway system. The nearby DDI at Miller Road opened in Aug. 2022 as part of the I-10 widening project. DDIs also have been constructed at I-17 and Happy Valley Road in north Phoenix and along I-10 at Houghton Road in the Tucson area. Two smaller diverging diamonds also are in use along the Loop 202 South Mountain Freeway in Phoenix.

ADOT works in partnership with the Maricopa Association of Governments on the planning and construction of new freeways, additional lanes and other improvements in the Phoenix area as part of the Regional Transportation Plan for the Maricopa County region. Projects are funded in part by Proposition 400, a dedicated sales tax approved by Maricopa County voters in 2004.