20 years of a complete 51

The year 2023 marks 20 years since State Route 51 was officially completed all the way from its starting point at the Interstate-10/Loop 202 “Mini-Stack” interchange to Loop 101 (Pima Freeway) in Phoenix.

A vital artery in Phoenix's transportation network, SR 51 has an interesting history that reflects the city's growth and development. Originally conceived in the 1950s as an official offshoot of Interstate 10, as I-510, SR 51 was designed to alleviate congestion and accommodate the increasing number of residents and businesses in the area.

In 1986, The City of Phoenix began construction of a parkway that served as the forerunner of SR 51 between I-10 and Glendale Avenue. Phoenix opened the first segment between McDowell Road and Glendale Ave in 1991, providing the beginnings of a crucial north-south connection through the heart of the city. The next year, Phoenix handed the reins to the road to ADOT, and thus began the job of extending the freeway north to Loop 101. ADOT also built the Mini-Stack interchange to provide a direct connection to and from I-10 and Loop 202 (Red Mountain) near downtown and Phoenix Sky Harbor International Airport

As Phoenix expanded, SR 51 became more than just a transportation route; it became ingrained in the city's identity. Who could forget the city’s neighborhood arts project that included the placement of elements, including various pots, atop the parkway’s barrier walls? While the city received some grief and the pots on the walls were removed during a freeway widening project some years ago, you can still see a teapot handle poking out near the Highland exit and several installed on the surface street sides of the 51. Many people never realized that the city’s project involved much more artwork in neighborhoods next to the original parkway. Many of those pots, from the project called “Wall Cycle to Ocotillo” still exist on the other side of the wall along either side of SR 51. The smaller vessels that once sat on the wall near Bethany Home Road were removed in 2004 when the height of the sound wall was increased. Those pots are now on display at the Deer Valley Water Treatment Plant.

The final segment between Bell Road and Loop 101 opened in 2003. Lane expansions and HOV additions were completed by 2008. And in 2016, the interchange with Loop 101 went through a slight adjustment with the addition of new ramps providing connections to and from Black Mountain Boulevard, providing improved access to the communities north of Loop 101. It was another example of building not just for today, but with the future in mind

Over the years SR 51 has grown from that simpler parkway closer to downtown into a major freeway route that truly opened much needed access to and from the northeast Valley.

ADOT over time also has done much work with cacti, plants and other elements to enhance the view for the tens of thousands of drivers who commute along the freeway each day. Views of the Phoenix Mountains Preserve alone often make it a good day to be on the road. Not to mention the five pedestrian and bike bridges (plus one tunnel!) that allow access to either side of the freeway.

Over the years, SR 51 has undergone several expansions and improvements to meet the demands of a growing population. The freeway's evolution mirrors the dynamic nature of Phoenix itself, adapting to the changing needs of the community it serves. 

Today, SR 51 stands as a testament to ADOT’s role in advancing the region’s economic development and supporting quality of life efforts, allowing people and products to get from Point A to Point B for work, recreation and business operations, in less time and with safety in mind. In the collective memory of many Phoenix residents, SR 51 is more than just a route; it's a thread woven into the fabric of the city's history, linking past, present, and future. Just ask someone who remembers riding a bike, jogging or walking on the pavement during ADOT’s community grand opening celebration held before the Shea Boulevard to Bell Road section opened to traffic in northeast Phoenix in the late 1990s.

State Route 51 remains a vital part of the Valley’s network of regional freeways, still going strong 20 years after that all-important Loop 101 connection was made.