I-10/Houghton Road DDI

I10-adot 0367

Ames Construction reconfigured the interchange at Houghton Road and I-10 in Tucson, Arizona, building the first diverging diamond interchange (DDI) in the city and the second in the state.

The 16-month project included the construction of a new, wider Houghton Road Bridge over I-10 just west of the existing bridge, widening Houghton Road to three lanes in each direction through the interchange, realigning Rocket Road on the north side of the interchange, and improving accessibility for bicyclists and pedestrians. Project scope included 15 drilled shaft foundations, storm drainage, retaining walls, and box culvert extensions.

Designed to handle heavier traffic while being safer for drivers, the DDI moves traffic over the bridge while briefly switching to the opposite side of the road to facilitate traffic flow. The reconstructed interchange increases the daily capacity of traffic from 8,000 to 50,000, providing relief for motorists accessing existing and planned residential and business developments in the growing region.

Learn more: Arizona Department of Transportation (ADOT)

Markets: Transportation, Roadways

Location: Tucson, Arizona

Client: Arizona Department of Transportation (ADOT)

Completion: April 2022


  • Earthwork
  • Bridge construction


  • Increased daily capacity from 8,000 to 50,000 vehicles a day

2022 Best Project
Category: Highway/Bridge
ENR Southwest

2022 Top 10 Bridges
Roads & Bridges magazine