State Route 189: International Border to Grand Avenue

The Arizona Department of Transportation and the Federal Highway Administration have completed an engineering and environmental study for SR 189 (Mariposa Road). Ames Construction and Horrocks Engineers have been selected as the “design-build” team to improve the roadway from the International border with Mexico to Grand Avenue in Nogales. The purpose of the project is to Improve traffic flow and safety. The improvements will include:

  • Widening approximately 3 miles of SR 189 from just north of the Mariposa Port of Entry to the intersection with Grand Avenue
  • Constructing a new roundabout at SR 189 and Target Range Road
  • Constructing new flyover ramps connecting SR 189 to Interstate 19 in both the north and south directions
  • Improving drainage Installing new traffic signals
  • Final Design Concept Report (August 2018)

Project Updates

Preliminary construction of the State Route 189: International Border to Grand Avenue design-build project has begun with utility relocation, clearing and set-up work. Major construction is scheduled to begin shortly on the new eastbound to northbound flyover ramp bridge. Temporary widening will also begin near Loma Mariposa Road.

Stay Informed

Schedules are subject to change based on weather and other unforeseen factors.  Subscribe to receive project updates and traffic alerts by email. For more information, please call the ADOT Bilingual Project Information Line at 855.712.8530 or submit a question or comment by email.  For real-time highway conditions statewide, visit ADOT’s Traveler Information Site at, follow ADOT on Twitter (@ArizonaDOT) or call 511, except while driving.