Newsroom | Prop 400 Means Upgrades for West Valley Freeway

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Transportation investments approved under Proposition 400 continue to result in upgrades along Loop 303.

Prop 400 Means Upgrades for West Valley Freeway
Loop 303 seeing 35 miles of improvements

Prop 400

Above: This overpass bridge replaced an at-grade crossing, making it easier to cross Loop 303 when traveling on El Mirage Road.

On the Move Partners in Progress logoUnder Proposition 400 in 2004, Maricopa County voters approved an extension of the half-cent sales tax for transportation. This series highlights projects built under Prop 400—to let you know where your money is going and how it is improving your transportation experience.

Transportation investments approved under Proposition 400 continue to result in upgrades along Loop 303, a major north south freeway in the West Valley. The freeway connects I-10 on the south to I-17 on the north, and carries 50,000 vehicles each day.

The improvements are steadily turning the 35-mile roadway from a four-lane highway to an access-controlled freeway.

One major project was construction of a new diamond traffic interchange at Loop 303 and El Mirage Road. The interchange opened in 2016, and included new overpass bridges, sound walls, lighting, pavement, drainage and other improvements. 

Before the interchange was completed, the intersection was a stop-controlled, at-grade crossing. The project included a full reconstruction of about one mile of Loop 303 and 0.2 miles of El Mirage Road.

The project cost about $25.8 million and is one of a number of interchange projects along Loop 303. The Arizona Department of Transportation plans to start construction later this year on the next segment slated for improvements: Happy Valley Parkway to Lake Pleasant Parkway. 

Proposition 400 was approved by voters in 2004 and extended the half cent sales tax for transportation by 20 years. It is set to expire in 2025.

Loop 303 projects with open to traffic dates

Project Opening Date
•    I-10/SR-303L System Interchange * 2016/2017
•    Peoria Avenue to Mountain View Road 2016
•    US-60/SR-303L System Interchange  2016
•    Cactus Road Traffic Interchange     2015
•    Waddell Road Traffic Interchange  2015
•    Bell Road Traffic Interchange 2015
•    US-60 to Happy Valley Parkway     2014
•    Happy Valley Parkway to Lake Pleasant Road 2014
•    Lake Pleasant to I-17  2014
•    Thomas Road to Camelback Road  2013
•    Glendale Avenue to Peoria Avenue 2013
•    El Mirage Road Traffic Interchange 2011
•    Camelback Road to Glendale Avenue 2011
* This was a phased project with two open dates.  


Published April 16, 2020


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