This Phoenix street was once part of transcontinental highway US 80

During the early days of Arizona’s roads, many local streets carried highway traffic, some of which were transcontinental highways. 

A great example is the 17th Avenue Underpass in downtown Phoenix, near the Arizona State Capitol. This structure once carried the tracks of the Southern Pacific Railroad over US 80. 

US 80 was a major transcontinental highway that ran from San Diego, Calif., all the way to Savannah, Ga. In Arizona, US 80 traveled from Yuma to the Arizona-New Mexico state line by way of Phoenix. At 17th Avenue, US 80 left Buckeye Road, heading north past the capitol to Van Buren Street.

The underpass itself was part of a Depression-era movement to eliminate on-grade railroad crossings. The structure was designed and completed in 1935 by ADOT’s predecessor, the Arizona Highway Department. It’s a concrete rigid frame with two 25-foot spans over the northbound and southbound lanes of the street. The deck was 80 feet wide to accommodate the multi-track railyards, with smaller openings for pedestrian sidewalks at both sides. The structure also incorporated decorative touches, like slotted concrete guardrails.

Interstates 8 and 10 gradually replaced US 80 and 17th Avenue now carries local traffic. The 17th Avenue Underpass is a well-preserved example of bridge construction of the time, as well as a reminder of what was an important transcontinental highway.