Interstates | US Highways | State Routes
Phoenix is the sixth largest city in the United States, an oasis in the middle of the Sonora Desert at the foot of the Superstition Mountains and the Mogollon Rim. Laid out in a grid pattern along the USGS land survey system, Phoenix is a relatively low-density, spread-out city. The freeway system is concentrated near downtown, with several state route freeways and the two Interstate highways clustering near the airport. Loop 101, completed in 2004, provides a partial belt route.
Freeways in Phoenix were developed rather late compared to most US cities. The first freeway was the Black Canyon Freeway (now Interstate 17), followed by I-10 east of I-17. These first two freeways were completed by 1970, and no new freeways opened for 9 years.
In 1973, plans were released for the Papago Freeway (I-10) through Downtown, along the Moreland Street corridor. Planners envisioned a freeway arching up to 100 feet above Central Avenue, with spiraling “Helicoil” ramps down to street level and parks underneath. The wife of Eugene Pulliam, publisher of the Arizona Republic, saw these plans and was horrified – so she convinced Pulliam to mount a campaign against the Papago Freeway.
Several votes later, freeway development in Phoenix was completely halted. Meanwhile, the city continued to grow dramatically, and traffic along with it. Some work had been performed on the Supersition Freeway (US 60, then signed as Arizona SR 360), but no other freeway work had been performed.
Phoenix Mayor Margaret T. Hance pushed through construction of the Squaw Peak Parkway (now Piestewa Freeway, Arizona SR 51) in the early 1980s as a city project from Interstate 10 to Northern Avenue. Meanwhile, the political atmosphere changed, leading to the passage of a 1/2 percent sales tax (Proposition 300) in 1985 to fund transportation. Construction of the valley freeway system began in earnest shortly thereafter.
In 2005, Proposition 400 was passed to extend the 1/2 cent sales tax another 20 years. Completion of Loop 202 and 303 is included in these funds, as well as two new freeways – Arizona SR 801 (I-10 reliever) and SR 802 (Williams Gateway Freeway).