highway in the vicinity of Toronto, Ontario, Canada.

This photo of a highway in the vicinity of Toronto, Ontario, Canada, illustrates how I-10 will look once the two collector-distributor lanes on either side of I-10 are completed.


Starting next week, billboards, social media, television and print media will carry messages urging thousands of Valley motorists, including those in the West Valley, to prepare for four years of disruptions in their driving routines.

It’s not exactly Armageddon that the Arizona Department of Transportation will be heralding, but it certainly won’t be a walk in the park either, especially for car and truck traffic on I-10. 

West Valley motorists who need to get to the other side of the county or Phoenix Sky Harbor International Airport can expect significant increases in traffic as motorists try to evade the inevitable tie-ups that will be caused by the I-10 Broadway Curve Improvement Project.

“There’s no way to sugarcoat it,” said ADOT spokeswoman Kim Noetzel, who, as an Ahwatukee resident, is bracing for the project. “It’s going to be impactful.”

Seven years in the planning, the work is ready to begin as crews scrape the asphalt along 11 miles of Interstate 10 between the junction of the San Tan and South Mountain freeways and I-17 near Phoenix Sky Harbor International Airport. 

Motorists will soon start feeling the impact later this year as work picks up steam on a project aimed at preventing virtually round-the-clock rush-hour gridlock on I-10 in the heart of Maricopa County.

“When the first phase of construction begins this summer, drivers should prepare for weekend closures on I-10 and U.S. 60,” ADOT spokeswoman Alexandra Albert said in a virtual briefing last week for Tempe residents. “And the reason for that is over the weekends, they’ll be closing down to remove the rubberized asphalt that exists on the roadway today on all of the travel lanes.”

With even more significant disruptions a certainty over the next four years, ADOT already wants commuters to prepare by studying and then taking different routes, especially if they work in downtown Phoenix.

The highway agency is going to unprecedented lengths to help them do that.

“We very much want to do everything that we can so that motorists, visitors and businesses can plan in advance to lessen the impacts,” Noetzel said. “We’re doing things with this project that we’ve never done before.”

In a virtual briefing last week, ADOT representative Alexandra Albert put it another way:

“ADOT is doing some really significantly different things than they have in the past, and it’s because of the size and the scope and the location of this project.”

For the first time, ADOT has developed a project-specific mobile app. It has prepared an advertising blitz on TV, radio and in newspapers. It’s ordered up billboards and even putting warnings and reminders on gas pumps. It has created a home page for the project at i10broadwaycurve.com where people can stay up to date and get the mobile app.

ADOT representatives have been briefing dozens of chambers of commerce and other economic development organizations from Glendale to Gilbert, holding town halls and planning to open a field office for the general public at 2157 E. Elwood Street in Phoenix where anyone can drop by Mondays to Fridays just to chat about the work.

All this, Noetzel explained, is being done “to create that awareness and make sure that people know where to get resources.”

Indeed, ADOT has spent two years talking with people about the project, she said, because “one of the underlying tenets of our communications approach in this is no surprises.”


A first and significant scope

ADOT calls the Broadway Curve project “the first major urban freeway reconstruction project in Maricopa County.”

Its major components include:

• Widening I-10 to six general purpose lanes and two high-occupancy vehicle, or HOV, lanes in each direction between U.S. 60 and I-17 and adding a fourth general purpose lane in each direction between Ray Road and U.S. 60.

• Adding collector-distributor roads that parallel I-10 between Baseline Road and 40th Street to separate through-traffic on I-10 from local traffic entering or exiting the highway. Unlike frontage roads along portions of the existing freeway system, these CD roads will not intersect with perpendicular roads.

• Rebuilding the I-10 interchange with SR 143 to improve traffic flow and create direct connections to and from SR 143 for drivers in the I-10 HOV lanes. This part of the project will reduce lane changes and often hair-raising weaving between Interstate 10 in the Broadway Curve and on State Route 143 at University Drive.  

• Razing and replacing the Broadway Road bridge over I-10.

• Replacing the 48th Street bridges over I-10 and widening the I-10 bridges over the Salt River.

• Building two bridges for pedestrians and bicyclists over I-10 between Baseline and Broadway roads (at Alameda Drive and the Western Canal) and improving the Sun Circle Trail crossing at Guadalupe Road.

• Installing a wrong-way driver detection system including thermal cameras, flashing signs and other specialized equipment that ties into ADOT’s intelligent transportation system.

Of the project’s total $776.6 million cost — less than half the cost of the South Mountain Freeway — $676.6 million will spent on construction, with $615.6 million going to  the developer, a joint venture of Pulice Construction, FNF Construction and Flatiron Constructors that goes under the name of Broadway Curve Constructors. 

The remainder of the project’s total cost covers the intelligent transportation system signal upgrades, right-of-way acquisition and paid advertising aimed at motorists. 

As a “design-build” project by a public-private partnership, meaning similar to one that produced the South Mountain Freeway, teams have one contract with ADOT for design and construction services. The project designers are T.Y. Lin International Group, Stanley Consultants and Aztec Engineering.

“Design build” also means that the contractors are “encouraged to use innovation and develop alternative concepts to reduce project time and impacts to the traveling public and community while construction is underway,” ADOT notes.


Better now than later

The Broadway Curve project covers roughly a third of the 31-mile I-10-/I-17 corridor that the Maricopa Association of Governments — the Valley’s major highway planning group — and ADOT call “The Spine” because it handles 40% of all Valley traffic daily.

The Spine is made up of a total of 37 access points, 40 bridges, 26 pump stations and 25 arterial streets that become snarled as a result of traffic jams on I-10 and I-17.

Combined daily east and westbound traffic already comes close to 300,000 vehicles through the Broadway Curve daily, and that number is expected to increase as the Valley’s population steadily grows.

ADOT Director John Halikowski at one point noted, “Interstate 10 is a key commerce corridor that supports Arizona’s efforts to succeed in the global trade market and a vital transportation route for millions of people who live in, work in and visit our state every year. Improving safety and reducing congestion will truly benefit everyone who relies on our highway system, as well as thousands of businesses along the I-10 corridor. We are proud to deliver a project that will improve quality of life for so many people throughout the region.”

Though the pandemic significantly reduced traffic volume, no one expects that to remain the case.

Traffic crawls are creating a phenomenon called “peak spreading,” which basically means rush hours get longer. If nothing is done, one ADOT study warns, by 2040, “congestion will spread to other times of the day, and in some portions of the corridor will extend to more than 12 hours.”

The 2018 study estimated it would cost at least $2.5 billion to cover all the improvements it recommends along the entire 31 miles of the Spine Corridor.

If nothing was done with the Broadway Curve, ADOT’s environmental impact study notes, it “would result in increased traffic congestion in the area as growth and development continue. This could impede travel to and from destinations and make it difficult to attract or retain businesses in and around the study area.”

“The level of congestion is anticipated to be more severe in various segments of the corridor, if no improvements were implemented and there is a need for improvements to maintain the functionality and mobility in this corridor,” it adds, warning:

“By year 2040, the traffic operations along the I-10 and interchanges in the study area would further degrade with the growth indicators forecasted for the foreseeable future. Without major improvements, the I-10 in the study area (the area covered by the Broadway Curve project) would suffer degraded traffic conditions, travel delays, and challenging mobility for moving goods, services and people through the study area.”

By doing something now, the study notes, “improved mobility and access along the corridor could foster economic development by attracting new business development and more attractive housing options and support social connectivity between neighborhoods and areas within the study area. This would represent a minor, positive, permanent secondary impact.”


The gain after pain

After the project’s pain comes what ADOT sees as a gain — not just for the 1,200 construction jobs it will create, but also for the future of more than 4,600 businesses that include 50 of the region’s largest employers.

Noting that I-10 “is part of a key commerce corridor that connects ports in California with markets in Texas and beyond,” ADOT’s environmental study states, “The improvements will make I-10 a more favorable route for commercial truckers whose travels through the region support our local businesses.”

 ADOT envisions the project will accommodate current and planned system linkages for bus services using I-10, facilitating more ride-sharing and rapid transit use.

Then there is the project’s overall impact on traffic, which ADOT describes thusly: “With the addition of new travel lanes, HOV lanes and the CD roads, capacity on I-10 will increase by 60 percent. This will better accommodate existing traffic and increased traffic as the region continues to grow.

“Adding capacity to I-10 will reduce congestion and travel times. Greater efficiency means drivers can get to and from the places they need to be in less time. According to an economic evaluation conducted by MAG in 2020, the improvements will save motorists 2.5 million hours annually otherwise spent in traffic — totaling $130 million a year in time savings. These savings are due to quicker commutes made possible by the improvements vs. slower travel times without them.”

 For motorists whose stomach knots in traffic, the study puts it another way:

“The current average speed on eastbound I-10 between I-17 and U.S. 60 during afternoon rush hour is 32 mph. The average speed is projected to increase to 40 mph by 2025 with the improvements. Without improvements, that speed limit is projected to decrease to 29 mph by 2025.”


But first, the pain

The environmental study reported, “Traffic delays and slower speeds would be experienced equally by everyone who lives or passes through the study area; therefore, all population segments, including low-income and minority populations, would be affected to the same degree by construction.

“Traffic operations would remain challenged, and congestion would become more prominent, particularly in the peak periods,” the environmental study anticipates, adding, “Construction could also affect local arterial streets in the study area. In addition to temporary traffic disruptions (closures and detours), construction traffic would be noticeable on area roadways and could occasionally contribute to localized congestion.”

During her briefing last week, Albert said, “This project will impact all of us, everyone who lives, works or drives to the project area.

 “In addition to the numerous freeway and ramp closures, there will also be significant overnight work that could be noisy. There will be temporary impacts on business access. There will be detours that increase driving distance and time. There will be slower traffic and will be delays. Unfortunately, there is no other way to deliver a project like this without having that kind of a construction.”

ADOT anticipates the I-10 will be shut down in both directions in the project area at least 50 times over the next four years. Most of these closures will occur on weekends, though some also will occur during the work week.

However, the detours, closures and lane restrictions the project will generate explain why ADOT hopes even occasional users of the freeways and byways impacted by the project will download the mobile app and pay attention to the other channels of communication it is deploying for the duration of the work.