You only have to work at the Arizona Department of Transportation for about five minutes to understand how passionate people are about their commutes. And rightly so. Travelers want to get to and from the places they need to be quickly and safely.

We understand closing a highway so we can work on it adds time, and sometimes extra miles, to a commute. With every project comes a balancing act of getting critical work completed while trying to reduce impacts to the traveling public. Many of you offer comments, questions and suggestions for us, which we appreciate.  Among the most common: 

“You shouldn’t close all of the lanes at the same time. When I lived in (enter another state here) they only closed a couple lanes at a time to do road work.”

“Why do you have to close the highways on the weekends?”

“You should do all of the work overnight when fewer people are driving.”

All fair points. But there is a method to the madness that we call “maintenance of traffic,” or MOT for short.

MOT comes into play when crews set up temporary construction zones on the highway system. While it’s critical to ensure movement of traffic through or around the work area, the foundation of MOT is keeping everyone - drivers, their passengers and construction crews - safe. That’s why closing all of the lanes is necessary at times.

Certain types of work over the travel lanes, such as relocating overhead power lines, taking down a bridge or setting bridge girders, cannot occur with drivers on the roadway below. The risk of potentially injuring travelers or damaging their vehicles is too great. Similarly, it’s not safe for workers to put down lane striping or set up concrete barriers on a multilane highway with thousands of vehicles driving by at 55, 65 and 75 mph. 

A project’s schedule is another factor in determining the size and scope of a closure. Fully closing a highway so 100% of the work is completed in one weekend can be a better alternative than partially closing the highway over three weekends so about 30% of the work is completed each time. Getting the work done more quickly benefits all of us. No one ever complains that a project finished too soon. 

That also helps to explain why not all of the work is done on weeknights, and why weekend closures are necessary. 

Weeknight highway closures are actually pretty common. Crews do a significant amount of work while most of us are sleeping. ADOT’s overnight closures generally occur from 9 or 10 p.m. to 4 or 5 a.m., ensuring the highway is fully open for your weekday morning commute.

Limiting a project to overnight work only - and not allowing for weekend closures - will undoubtedly add time (and cost) to a project. Consider this:

Closing a freeway between a Friday night and a Monday morning provides about two full days for work to get done (after you subtract the hours needed to set up and take down the traffic control barriers and signs).

If a project has 25 weekend closures in a year that adds up to 50 work days. Over the course of a three-year project, it’s 150 work days - or five months.

Finishing a project five months earlier is a good thing; motorists get to take advantage of the improvements sooner and - depending on factors such as fuel prices and inflation rates - the project will often cost less. 

We know many people are out and about on the weekends. Yet, an even greater number of people use our urban highways on weekdays. Although we saw a dip in traffic volumes during 2020, our urban highways are back to pre-pandemic levels during the work week. 

That doesn’t mean work won’t get done on week days. We collaborate with our contractors to develop schedules that allow them to have crews in the field without impacting drivers. On the Interstate 10 Broadway Curve Improvement Project, for example, work is happening on weekdays, but behind concrete barriers in the median of I-10 and on the outside of travel lanes. This allows our workers to make progress while we fully maintain all of the travel lanes zone during peak travel times.  

We can also make considerable progress - and more quickly - by allowing extended closures of on or off ramps. For example, the I-10 Broadway Curve project team is planning to close the ramps 32nd and 40th streets for up to 45 days each to make improvements. Both ramps won’t be closed at the same time, however, so motorists will have a convenient, nearby alternate route. Extended ramp closures like these make it possible for crews to establish a work zone and keep it in place until they’ve completed the job. Again, this is a more time- and cost-efficient method vs. setting up and tearing down the work zone daily.

What you might not know is we don’t schedule work that requires highway closures during our “holiday moratorium,” which begins in mid-November and continues until the first work day after New Year’s Day. We also don’t close a highway that provides access to a special event with 30,000 or more people. Our highways also remain open over state holiday weekends when we know more drivers will be out enjoying our beautiful state.

Unless there is an unplanned incident on or next to the highway (crashes, wildfires, for example) we strive to provide as much information as possible in advance so you can plan ahead. We encourage you to allow extra travel time and use the detours we provide. You can also download the free AZ511 app to get real-time highway conditions statewide.

We work hard every day to achieve our vision of becoming the safest, most reliable transportation system in the nation - but sometimes that means we need to close a road. 

As March turned into April, Arizona Department of Transportation crews working near the international border in Nogales celebrated the first anniversary of work on State Route 189 the way only roadbuilders can: Moving the last of a combined 8.5 million pounds of concrete-and-steel girders into place.

Last March, Governor Doug Ducey, along with government and business leaders from southern Arizona, broke ground on a project that is expected to create economic growth in Santa Cruz County while making one of Nogales’ busiest roads safer and less congested. 

ADOT is building two ramps connecting SR 189 with Interstate 19. When the work is complete this fall, the ramps will make Nogales a more attractive place for international commerce to enter the US. That’s significant; the Mariposa Port of Entry saw about $25.5 billion in imports and exports in 2019, including much of the winter produce consumed in the U.S.

They’ll also save trucking companies time and money by eliminating the need to stop at three traffic signals, and they’ll make SR 189 safer for Nogales High School students who will no longer have to navigate around those trucks to get to school.

The ramps provide an impressive site for southbound drivers on I-19. The northbound ramp runs for just more than half a mile, while the southbound ramp is just more than one-third of a mile long. They come together just west of Frank Reed Road. The ramps include 122 girders, each averaging about 70,000 pounds and 135 feet long.

Between now and when the work is complete, crews will be pouring concrete decks on the ramps, finishing a new roundabout at Target Range Road and completing the remaining tasks to make SR 189 better for Nogales, better for international trucking and better for Arizona’s economy.

“Better roads,” Governor Ducey said at last year’s groundbreaking, “mean a better future for Arizona.” 

In Nogales, that better future is just a few months away.

It’s not always clear to drivers why crews need to stop traffic in a work zone, but there was no mistaking what was happening for nine days this month on State Route 77 in Winkelman.

A pair of massive cranes moved huge concrete girders into place over the Gila River as part of a bridge replacement project that began in September 2019, in what was one of the most eye-catching steps of the process.

The 24 girders ranged from about 113 feet long and 80 tons to about 138 feet long and 100 tons. Those girders will form one half of the new structure that spans about 761 feet. The other part of the bridge was completed earlier this year and is now carrying a single lane of alternating traffic until the project is expected to be completed by early summer.

The work zone will remain a busy place through the first half of 2021. Crews will pour the concrete deck above the recently-placed girders by late January. The work will occur at night, and the single lane across the bridge will remain open during that operation.

Through the spring, crews will install concrete barriers, a new and wider pedestrian path, and guardrail. Toward the end of the project, expect pavement work and lane striping at either end of the bridge. A signal will continue to regulate traffic flow and drivers should allow for extra travel time. For more information, to view the schedule or sign up to receive traffic alerts, please visit the project page.

It is an operation that requires planning, steady hands and a focus on safety. Oh, and let’s throw in another word: measuring. We’re talking about the recent placement of more than 20 steel girders at Interstate 17 and Central Avenue in Phoenix, where the first half of ADOT’s reconstruction of the old freeway bridge continues to advance.

As you can see in our accompanying group of ADOT photos, these are large and heavy girders. Project crews worked earlier in November to lift them into place with cranes, followed by the important work to safely secure them with bracing.

To be a bit more descriptive, these are Continuous Welded Steel Plate Girders. Each of them is 80 to 88 feet long and each tops the scales at between 12 and 15 tons.

For this part of the I-17 bridge project at Central Avenue south of downtown, three girder sections were placed end-to-end in seven rows, also known as girder lines. They will provide the support for what will be the southbound lanes of the freeway when all is said and done in 2021.

These girders are now secured with steel plates that are installed every 16 feet between the side-by-side girder lines. And before you bolt from reading this, give some thought to how many bolts are used in this whole process. Don’t go “nuts” when you learn the answer is more than 6,500 bolts for the entire new structure. It’s all about strength, security and safety.

The focus of this $13.5 million project so far has been on rebuilding the southbound side of the bridge over Central Avenue. The original I-17 bridge was opened to traffic in 1962. Working in phases, crews earlier this year demolished the old southbound structure to make room for the area where these new girders are now located. Freeway traffic is currently shifted and thus temporarily sharing the existing northbound side of the bridge.

ADOT’s project team plans to complete the modernized southbound side of the bridge early next year. That’s when all I-17 traffic in the area will be shifted to the new structure so that reconstruction of the northbound side can move ahead. 

That second major phase in 2021 will include placing an additional 27 of these big girders to provide a wider bridge that will be able to accommodate more lanes along I-17 when future funding is available. So there’s still lots of heavy lifting ahead at I-17 and Central Avenue. 

By Tom Herrmann / ADOT Communications

The last time you went to the gym, how much weight did you lift? More than 100 pounds? 200?

More than 75 tons, anyone?

Those building a new bridge connecting Interstate 10 and State Route 87 in Eloy didn’t really lift 20 tons, of course. But 30 feet above the ground today, as two cranes lifted huge girders into place, these professionals, securely perched atop bridge piers, made sure these 145-foot girders landed in just the right spot.

And they repeated the process over and over, as shown in the slideshow above.

Precision may be difficult with a heavy girder, but it’s essential. There needs to be the right number of girders across each pier to support the bridge deck and traffic over decades. And each girder must allow room for the one that will connect to the next pier.

Today marks six months since crews began clearing ground for new lanes of I-10 and the new interchange with SR 87. Placing girders on the bridge is another visible sign that work is continuing on schedule.

The project is creating six new lanes of I-10 that will connect with the existing freeway just west and a few miles east of SR 87. Traffic will be moved to the new pavement as soon as this fall, with the entire project scheduled for completion by fall 2019. After this project and another in Casa Grande are complete, I-10 will be three lanes in each direction all the way between Casa Grande and the east side of Tucson.

By John Dougherty / ADOT Communications

The first of 1,100 girders planned for the Loop 202 South Mountain Freeway have gone up at 17th Avenue and 40th Street along the Pecos Road corridor.

The 17 steel-reinforced concrete girders are 145 feet long, weigh up to 131,000 pounds and take an hour each to hoist in place.

The ADOT Flickr slideshow above shows the result of recent work at 17th Avenue.

The Loop 202 South Mountain Freeway will add 22 miles of highway to the Phoenix freeway system, connecting the east and west valley. The freeway is expected to start taking traffic in late 2019.

Learn more about this project and sign up for alerts at SouthMountainFreeway.com.

By Caroline Carpenter / ADOT Communications

Setting girders for an overpass carrying Bell Road across Grand Avenue (US 60) in Surprise is another sign that ADOT is on track to: (1) reopen Bell Road by November; and (2) create a modern traffic interchange that will relieve traffic congestion.

Check out the time-lapse video above and the photo slideshow below to see the latest progress on this $41.9 million project.

Bell Road has been closed between Dysart and Litchfield roads since April 1 to ensure the overpass reopens before the holiday shopping season kicks off. The entire project, with ramps to and from Grand Avenue, will be completed by next spring.

In all, 89 steel-reinforced concrete girders will be set in place. They range from 67 to 158 feet in length and weigh up to 90,000 pounds.

Crews have also been building a new wider section of the westbound lanes of Grand Avenue near Bell Road. When major portions of the bridge deck for the east half of the overpass are in place, plans call for Grand Avenue traffic to be switched to reconstructed westbound lanes beneath the Bell Road overpass structure.

Work on the Hell Canyon Bridge replacement project is really moving along…

As you can see in the video above, crews are placing girders for the new, wider bridge set to replace the 1950s-era bridge that drivers use today.

The work is all part of a $14.4 million improvement project that includes the construction of the new bridge (it’ll be a four-span steel-plate girder bridge), the eventual removal of the old bridge and some additional road construction/realignment work to the north and south of the new bridge.

The new 665-foot-long two-lane bridge will feature wider travel lanes and will be approximately 47 feet wide, more than 17 feet wider than the current bridge. The bridge will also accommodate heavier loads, making it more convenient for commercial trucks to carry goods and produce to their final destinations.

This project animation gives a good look at what to expect as the work progresses. See some recent photos of the project on our Flickr page.

With hundreds of blog posts in our archives, we understand if you haven’t had a chance to read them all.

However, there’s a lot of interesting content in those early posts and we don’t want you to miss out. That’s why we’re looking back and highlighting some of our favorites in a new series called, “From the Rearview Mirror.”

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Originally published on Aug. 29, 2011, the video featured in this post gives a dizzying look at a girder installation (we’ve blogged about girders a couple of times since then).

This post also refers to the reconstruction of the Mescal/J-Six Bridge, which you might remember was completed in September 2011.

Tiny camera captures bird’s eye view of girder installation

If you’ve been following along in the blog, you know that we’ve been chronicling ADOT’s reconstruction of the Mescal/J-Six bridge in southern Arizona since it was severely damaged when two semi trucks collided underneath it back in March. Completion of the fast-tracked bridge reconstruction is slated for later this month.

Here's a shot of the GoPro in action. The inset photo gives you an idea of how small the camera really is.

Last week, crews installed 35,000-50,000 pound girders and our video team wanted to explore a creative way to take you behind the scenes of what goes into placing a 25-ton piece of concrete.

To get the perfect shot, they looked to a GoPro® Hero. GoPros are tiny (1.6” x 2.4” x 1.2”, 3.3 oz) HD cameras that let photographers get some incredible shots they never would have been able to otherwise.

Conditions weren’t exactly ideal (check out our Facebook page for pictures of the tarantula and other creepy crawlers that joined their shoot and the extreme weather that loomed in the distance), but they couldn’t miss a chance to secure a GoPro to one of those massive girders! (You might want to sit down before watching this one…it may make you a little dizzy.)