Interstate 10 ramps reopen at Houghton Road after reconstruction

New ramps signal progress on diverging diamond interchange project

Ramp at Interstate 10/Houghton Road interchangePHOENIX – Two ramps on the east side of the Interstate 10/Houghton Road interchange in Tucson have reopened, restoring full access to drivers as the Arizona Department of Transportation makes progress on a project to rebuild the interchange.

Motorists are now able to use the eastbound on-ramp from Houghton Road to I-10 and the westbound exit ramp from I-10 to Houghton Road. The ramps closed in late August for reconstruction.

The new ramps, along with new bridge piers for the future Houghton Road bridge, are the most significant improvements to date on a $24.4 million project to improve safety and traffic flow in the rapidly growing area east of downtown Tucson.

The new interchange will be an innovative design called a diverging diamond, a configuration where traffic on Houghton Road will make a temporary shift to the left side of Houghton Road while crossing the freeway. This allows for left turns onto entrance ramps without waiting at an additional traffic signal. This design promotes safety because drivers turning left don’t cross traffic while entering the on-ramp.

The new Houghton Road bridge will feature six lanes of traffic, compared with two lanes on the existing structure. Also, the project will improve access for pedestrians and bicyclists.

The two ramps on the west side of the interchange will be rebuilt without extended closures, as ADOT has developed a construction plan that allows those ramps and the new bridge to be constructed with only occasional nighttime closures.

The project is scheduled for completion in late 2021.

More than 115 diverging diamond interchanges are in use in the U.S. as of mid-2020, including a full diverging diamond interchange that opened at Interstate 17 and Happy Valley Road in Phoenix this month.

For more information about the project and diverging diamond interchanges, please visit