Fourth westbound Loop 101 lane opens from 51st to 75th avenues

Drivers on westbound Loop 101 now have a fourth regular travel lane between 51st and 75th avenues, marking another visible step in a $140 million widening project across the Northwest Valley.

The Arizona Department of Transportation opened the lane after a late-August weekend closure. The new segment extends the added westbound capacity farther west after ADOT opened portions of a fourth lane between Interstate 17 and 51st Avenue earlier this year.

The work is part of ADOT’s ongoing Loop 101 widening project between 75th Avenue and I-17, which began in September 2024 and is scheduled for completion in spring 2027. ADOT says the project is intended to address growing traffic demand along the Agua Fria Freeway corridor through north Phoenix, Glendale and Peoria.

What the $140 million project is changing

The freeway project goes beyond the newly opened westbound lane. ADOT is adding one general-purpose lane in each direction between 75th Avenue and I-17. Crews are also widening bridges at 51st, 35th and 31st avenues, modifying ramps and frontage roads in some locations, upgrading freeway drainage and lighting, resurfacing pavement and rebuilding or modifying noise and screen walls where warranted.

At 75th Avenue, the project includes a third southbound left-turn lane for drivers entering eastbound Loop 101. ADOT is also adding capacity to the westbound Loop 101 ramp to northbound I-17 and a new northbound I-17 lane between Loop 101 and Pinnacle Peak Road to accommodate traffic entering from the expanded ramp.

Those interchange improvements remain under construction. ADOT said in its Aug. 31 project update that other new-lane segments and improvements, including additional entrance capacity along southbound 75th Avenue, are still being built.

More capacity is open, but construction continues

The new 51st-to-75th Avenue lane is a project milestone rather than completion of the corridor. Drivers should still expect periodic restrictions and closures while remaining work continues. ADOT has said construction may require overnight and weekend lane restrictions, full freeway or ramp closures and some longer-term ramp closures.

The project is funded through Proposition 400, the Maricopa County transportation sales tax approved by voters in 2004 and incorporated into the regional transportation plan managed by the Maricopa Association of Governments.

For Northwest Valley commuters, the practical change is already visible. Westbound Loop 101 now carries four regular lanes across the newly opened segment from 51st Avenue to 75th Avenue, while the broader freeway and interchange work continues toward its planned 2027 finish.

Featured image: Loop 101 at the Interstate 17 interchange in north Phoenix, photographed Sept. 11, 2010 by Alan Stark. The image is archival and does not depict the current construction work. Source: Wikimedia Commons, licensed under CC BY-SA 2.0. Image resized for publication.