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Diverging diamond interchange planned for I-10 east of downtown Tucson

Open house on Houghton Road design scheduled for Thursday, Feb. 8
February 05, 2018

TUCSON – Those living and working in one of Pima County’s fastest-growing areas will be able to access Interstate 10 more efficiently and safely using a new style of traffic interchange planned at Houghton Road east of downtown Tucson.

Arizona Department of Transportation engineers will introduce a diverging diamond interchange, the first of its kind in Pima County, at an open house scheduled from 5:30 to 8 p.m. Thursday, Feb. 8, in the auditorium at Empire High School, 10701 E. Mary Ann Cleveland Way. From the Houghton exit on I-10, go north on Houghton about one mile to Mary Ann Cleveland Way, then go east to the school.

“We’re using the latest in freeway design to better accommodate the needs of this community,” said Rod Lane, district engineer for ADOT’s South Central District. “The diverging diamond design will help move traffic efficiently, and, by reducing the number of conflict points where vehicles cross paths, make this interchange as safe as possible.”

In a diverging diamond interchange, local street traffic makes a temporary shift to the left side while crossing the freeway, allowing for direct left turns onto entrance ramps without waiting at an additional traffic signal. This design is a good fit for the growing southeast Tucson area because it can handle higher traffic volumes. It also promotes safety because drivers turning left don’t cross traffic.

Traffic on I-10 in eastern Pima County is expected to increase by as much as 50 percent by 2045, and traffic on Houghton Road is expected to increase by 500 percent north of I-10 and 200 percent south of the freeway. The reconstructed interchange will provide relief for motorists accessing existing and planned residential and business developments in the surrounding areas. The project also includes reconstructing Houghton Road on both sides of the freeway.

More than 80 diverging diamond interchanges have been built in 29 states since 2009. ADOT also has announced plans for diverging diamonds at Interstate 17 and Happy Valley Road in Phoenix and at two South Mountain Freeway interchanges.

Those attending the open house can view plans for the interchange, ask questions of ADOT designers and offer comments and suggestions. Those who are unable to attend can provide comments or ask questions by calling the ADOT Bilingual Project Information Line at 855.712.8530, sending an email to or by sending written comments to ADOT Communications, 1655 W. Jackson Street, MD 126F, Phoenix, AZ  85007.

The Houghton interchange is scheduled for construction to begin in 2020.

For additional information, please visit the project website at

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De acuerdo con el Título VI de la Ley de Derechos Civiles de 1964, la Ley de Estadounidenses con Discapacidades (ADA por sus siglas en inglés) y otras normas y leyes antidiscriminatorias, el Departamento de Transporte de Arizona (ADOT) no discrimina por motivos de raza, color, origen nacional, sexo, edad o discapacidad. Las personas que requieran asistencia (dentro de lo razonable) ya sea por el idioma o discapacidad deben ponerse en contacto con la Oficina de Derechos Civiles de ADOT en Las solicitudes deben hacerse lo más antes posible para asegurar que el Estado tenga la oportunidad de hacer los arreglos necesarios.