EDITOR'S NOTE: During Infrastructure Week 2019, we're highlighting aspects of construction, improvement and maintenance that are part of Arizona's $22.4 billion investment in state highways. Today's Throwback Thursday post takes you back to some of the many ADOT projects in recent years that have improved the quality of life around Greater Arizona.

By Steve Elliott / ADOT Communications

Here at the ADOT Blog, there's just nothing better than video to illustrate how transportation investments benefit communities around the state. Case in point: the video above from a 2017 project that used an innovative technique to create a bridge in just 96 hours in northwestern Arizona.

So without my words getting in the way, at least too much, let's continue Infrastructure Week 2019 with a Throwback Thursday exploration of some projects completed in recent years around Greater Arizona, as featured in ADOT videos.

It's no secret that we're awfully excited to now have drones, funded by a federal grant, to help tell ADOT's story. That led to this aerial view from February explaining a project improving traffic flow and safety on State Route 347 in Maricopa. The work, finishing later this year, includes creating a bridge carrying traffic over the Union Pacific Railroad tracks.

This September 2018 video used one of our new drones, along with some magic at the production end, to highlight improvements that are part of a project widening several miles of I-10 near Eloy. The work has advanced considerably since this video was made, and the project will be wrapping up later this summer.

Next up is a May 2018 video explaining how ADOT worked closely with businesses in Seligman on a project, now wrapping up, reconstructing the decks of three bridges along one of two routes between the Route 66 community and I-40. In addition to a project timed to affect just one summer, the community will have bridges ready for additional decades of use.

ADOT invests in preserving highways around the state, but sometimes a full rebuild is in order, as was the case with a project that replaced 5 miles of I-40 in each direction just west of Williams. The pavement in this area was stressed from years of freezes and thaws common to highways in Arizona's high country. This 2017 video, made a year before work wrapped up last fall, shows what went into the $34 million project.

Sometimes making an improvement, such as creating a modern State Route 89 bridge at Hell Canyon between Chino Valley and Ash Fork, requires removing what came before. This 2016 video shows the demolition of the previous Hell Canyon Bridge.

Infrastructure and jaw-dropping surroundings make for incredible video, as was the case with a $27 million project, completed in 2016, that rehabilitated Interstate 15's Bridge No. 6 in the Virgin River Gorge of far northwestern Arizona. Do note that another project to upgrade other bridges in that stretch is scheduled to begin after Memorial Day.

It's been several years now, but I'd be remiss to feature videos of improvements in Greater Arizona without showing ADOT's efforts to restore US 89 after a catastrophic landslide south of Page. This 2015 video provides two views of this project.

And these videos are just a start. To see more, please visit and subscribe to ADOT's YouTube channel at youtube.com/ArizonaDOT.

By David Rookhuyzen / ADOT Communications

As we shared this week, ADOT has reached a milestone at the Loop 202 South Mountain Freeway interchange rising at I-10 in west Phoenix. During a weekend closure of eastbound I-10, crews placed the last 21 of 186 bridge girders that will support transition ramps.

Though there is still plenty of work left to do, at a moment like this its always nice to zoom out a little and see what we've accomplished so far. You can do that with the video above as we show you an overview of the five future ramps and some of the finer architectural details.

To learn more about this interchange and other aspects of ADOT's largest single highway project ever, please visit SouthMountainFreeway.com.

By Steve Elliott / ADOT Communications

Sometimes showing beats telling by a country mile. That's the case with our recent use of a product called Boulder Busters to remove a massive rock that slid down the slope next to State Route 88 east of the Valley.

With words and images, including some shot from a drone, the video above shows how ADOT workers went about removing this boulder in a way that minimized traffic impacts while reducing the potential for damage to the roadway and for more rocks to tumble down the slope.

By Tom Herrmann / ADOT Communications

At the groundbreaking for a State Route 347 overpass in the heart of Maricopa, officials spoke with pride about the work done for more than a decade to make this $55 million improvement a reality.

For most of the past year, the site at SR 347 and Maricopa-Casa Grande Highway has looked pretty much as you would expect: like a job site. But late next week it will begin to look much more like the overpass that will open up the community by ending the regular waits for trains to pass.

Thursday night, March 28, Arizona Department of Transportation crews are scheduled begin pouring the concrete deck for the overpass. About 130 cement trucks will bring in about 1,300 cubic yards of concrete to form the deck of the overpass, which will be 318 feet long, 130 feet wide and carry six lanes of traffic.

The deck pour is a good opportunity to take stock of all the things crews have achieved in Maricopa since work began in spring 2018. We built an entire new road, Plainview Street, near the Maricopa Unified School District offices. Towering piers that will hold the overpass, about 20 of them, are in place, along with earth and decorative mechanically stabilized earth panels that will form the walls at each end of the overpass. We’ve cleared ground for the new SR 347 alignment and done hundreds of smaller tasks, such as moving utility lines, that are important but unseen parts of a big job like this.

Plenty of work remains. Nothing is larger than creating the foundation and laying pavement for the new road surface, but there are dozens of tasks still to be completed before the road is ready for traffic near the end this year.

Take a look. We think you’ll be happy with how far we’ve come.

By David Rookhuyzen / ADOT Communications

As long as there are freeways and highways there will be road work. And that means construction zones.

Though we try to schedule as much road work as we can for times when most drivers aren’t on the road, that isn’t always possible. We want both you and our crews to get home safely, so here are few tips for driving through a work zone:

Slow down: It's one of the simplest and most important things drivers can do, as speeding is one of the major causes of work zone crashes.

Keep a safe distance: Most crashes that happen in a work zones are rear-enders, so we recommend keeping two car lengths between you and the car ahead and maintaining space between your vehicle and construction workers and their equipment.

Pay attention: Observe all posted signs; they are there to help traffic move through the work zone as safely as possible.

Obey flaggers: A flagger has the same authority as a posted sign and knows how traffic should be flowing through the area.

Expect the unexpected: Be prepared for changes in speed limits, lane restrictions and people working near the road.

Those are just a few common-sense items that go a long way toward keeping drivers and crews safe in construction zones. You can find more tips and some frequently asked questions at our work-zone safety website.

By David Rookhuyzen / ADOT Communications

We launched our ADOT Alerts App in 2017 to keep drivers as informed as possible about highway closures on their routes so they can plan accordingly. Thousands more Arizona drivers showed they valued that technology last week as a heavy winter storm dumped snow and rain across the state.

Last week, 6,000 people downloaded the free app, which is available for iOS and Android at ADOTAlerts.com. For the entire month of February, 8,000 people came on board, compared to average increases of 2,500 users per month in 2018.

During the storm, we constantly updated an alert to reflect which highways were closed due to winter weather and which had reopened after our crews cleared snow and ice.

Using geofences, the ADOT Alerts App sends notifications to smartphones when a nearby state highway has an unplanned closure due to an event such as a crash and or heavy weather, when a construction project will close a major freeway for an extended period and when a major route such as Interstate 17 north of the Valley is seeing extreme delays.

The app does not require a user to register or log in to use. You can learn more about it on our website.

By Doug Nintzel / ADOT Communications

It wasn’t the Oscars, and, more importantly, it was about highway safety. As the video above shows, ADOT was in the spotlight at a recent ceremony in Washington D.C., when a national group honored one of the agency’s creative safety solutions.

The National Operations Center of Excellence presented its Best Transportation Systems Management and Operations (TSMO) Project Award to ADOT’s US 60 Superstition Freeway Improvement Project in Tempe. Representatives of ADOT’s own Transportation Systems Management and Operations division were on hand to accept the honor.

For the Superstition Freeway project, an ADOT team evaluated a section of westbound US 60 between Mill Avenue and the I-10 interchange where a concerning number of crashes, most of them minor, had resulted backups during busy periods.

In collaboration with the city of Tempe and the Arizona Department of Public Safety, ADOT adjusted lane striping and installed new signs along that stretch of westbound US 60 in summer 2018. The result: improved traffic flow in the left lanes, leading to a significant reduction in crashes. The video features an ADOT engineer who worked on this project explaining its effects.

The National Operations Center of Excellence serves as a nationwide resource for the Transportation Systems Management and Operations community. Its partners include the American Association of State Highway and Transportation Officials, the Intelligent Transportation Society of America and Institute of Transportation Engineers. The Federal Highway Administration also supports the effort.

ADOT’s Interstate 17 Wrong-Way Vehicle Alert System being tested in Phoenix also received a national runner-up award in the competition.

By David Rookhuyzen / ADOT Communications

Today we're using a drone to provide a different perspective on work demolishing the old I-10 bridges over Jimmie Kerr Boulevard in Casa Grande, part of a project widening 4 miles of the interstate to three lanes in each direction.

In between the bridges that are on the way out, you can see new bridges over Jimmie Kerr Boulevard. On Jan. 9, we moved traffic to these bridges.

After the old bridges are removed, crews will add another lane and a full shoulder to each of the new structures.

The project is scheduled for completion in late summer at roughly the same time as another widening project just to the east between Eloy and Picacho.

By Tom Herrmann / ADOT Communications

On most road-building projects, there’s a lot of work you don’t see. From building foundations for new travel lanes to pouring concrete deep into the ground to support bridges, the progress isn’t always visible to drivers passing by.

As you can see in the video above, that’s been anything but the case on the project widening 4 miles of I-10 between Eloy and Picacho. Over the past six weeks, here’s what has happened:

• Westbound traffic moved to the new westbound lanes in early December.
• Crews removed the pavement, bridges and guardrails from the old westbound lanes.
• Eastbound traffic has been moved to new pavement that eventually will be used for westbound traffic, separated from westbound traffic by concrete barrier.
• The new overpass connecting I-10 with State Route 87 has opened, including both westbound ramps and a temporary eastbound ramp.
• SR 87 has opened north of I-10, allowing traffic to connect from the freeway to central Arizona.

Next up: Removing the old eastbound lanes, finishing construction of the new eastbound lanes and implementing the innovation dust detection system designed to give drivers information to make them safe in a dust storm. We're also recycling asphalt and other materials to create the base for the new eastbound lanes.

It's all scheduled to be done by early fall.

By Tom Herrmann / ADOT Communications

Every time you drive by an overpass, you see the cement-and-steel columns that support the roadway. There could be only a few on a small overpass, or more than a dozen in larger overpasses like the ones at two current projects on Interstate 10 in Pinal County. They usually hold the overpass 15-20 feet above what's below.

What you don’t see is just how low they go.

A typical bridge column drops down about 80 feet underground – about the height of an eight-story building.

Each pier includes a cylinder of rebar steel about 6-8 feet in diameter, woven into a lattice that creates hundreds of squares no more than 1 foot across. Each of those squares is tied together – by hand – to strengthen the concrete that is poured on top to create what's known as a caisson (this 2011 video shows the process).

Why so deep? Friction.

The bridge columns are in place not only to hold the overpass up but to keep it steady. It’s essential that each overpass be held firmly in place. The deep columns create friction with the surrounding ground, preventing the bridge from moving despite thousands of vehicles crossing a typical overpass every day, and weather bringing rain and crosswinds. Combine 10 or more columns and the friction is enough to hold a bridge steady for decades.

Overpasses like the ones being built today in places like Maricopa and Tucson are built to last 50 years or more. One way to make sure they serve that long is to give them a good foundation. By digging so deep, ADOT is doing just that.