Highway construction is and has been labor-intensive, but after we found this photo we couldn't be happier to be living in our modern, mechanized age.

Because these folks here driving the livestock are not farmers out plowing a field. They are actually Arizona Highway Department crews in the process of grading a highway. US 60 between Salome and Aguila, to be exact. This mule-driven photo is from Dec. 7, 1933.

As you might know, grading is the process of smoothing the base layer of a road to remove divots, washboards and other high or low points. For dirt roads, such as this stretch of US 60 (which would also be co-signed with US 70 for a time), grading is basically all the roadwork and maintenance that is done. Today construction crews have grading machines for this type of work. We can only imagine those machines are a bit more reliable than the mules and produce less ... um ... waste.

The year this photo was snapped is significant because it was actually a bit of turning point for highway construction in Arizona. According to our report on the state's transporation history, that year the federal Public Works Administration gave Arizona $5.2 million for road projects, which covered hundreds of miles of grading and draining, oiling, sealing and paving, along with bridge construction, shoulder-widening and railroad-crossing construction.

By 1933, Arizona was also the leading state in the West when it came to oiling, or spraying "low-type bituminous surfacing" on, gravel roads. At the start of the year, more than 1,000 miles of state highways had been oiled, and when State Route 87 in Chandler was surfaced, for the first time a person could drive between Phoenix and Tucson without driving on a single stretch of a gravel road. At the end of 1933, the state reported that all its highways, with limited exceptions, had been oiled or actually paved.

That's all fascianting for us, but it most likely meant little to our mule-driving friends here, who were probably just happy if their stubborn charges kept the grader moving.

The important ongoing project to reconstruct the Interstate 17 bridge over Central Avenue south of downtown Phoenix remains in an early stage. But before the work got started, our staff at ADOT knew the bridge work zone would present challenges for drivers who use the stretch of I-17 between the I-10 “Stack” and “Split” interchanges.

A decision was made to incorporate a “Smart Work Zone” safety innovation into the I-17 project at Central Avenue. As you can see in this ADOT video, the project team has followed through with the placement of portable message signs on trailers at nearby freeway locations to provide drivers with travel times for both I-10 and I-17 in the downtown area.

For example, one of our message signs along westbound I-10 near Phoenix Sky Harbor International Airport provides both I-10 and I-17 travel times. That allows drivers to compare the estimated travel time for using northbound I-17, which includes the work zone, or what to expect by staying on I-10 in the downtown area.

On average, the optional I-10 route that includes traveling through the Deck Park Tunnel is saving drivers five or more minutes of commute time, not to mention avoiding the frustration associated with slow moving traffic in a work zone. Even with lighter traffic conditions on freeways during the current health situation, there are times when slow downs and backups occur on I-17 in the area approaching the bridge work at Central Avenue.

The portable sign system uses traffic data to calculate the estimated travel times to predetermined destinations. This system is much like the one used to provide drivers with valuable travel times on ADOT’s permanent electronic message boards along Valley freeways.

As part of this pilot project, portable message boards also have been placed in areas along I-10 approaching interchanges connecting to the new Loop 202 South Mountain Freeway. Those signs also provide drivers with estimated travel times for using either Loop 202 or I-10 through the downtown Phoenix region.

ADOT has recently established several Smart Work Zone initiatives to help offset challenges associated with keeping traffic moving while construction is taking place. Those innovations include an I-15 queue warning system in the Virgin River Gorge, providing drivers with information to prepare for stop-and-go conditions ahead. Another example is the I-40 dynamic merge system east of Flagstaff that adjusts methods for merging depending on conditions near a bridge project at Meteor Crater.

EDITOR'S NOTE: During this unprecedented time, ADOT is creating transportation activities for kids. Please visit azdot.gov/ADOTKids or use the hashtag #ADOTKids on ADOT's Twitter, Facebook and Instagram accounts to see what we have going on.

By Steve Elliott / ADOT Communications

I hope you've enjoyed our latest ADOT Kids activity focusing on the Loop 202 South Mountain Freeway and how we use designs and landscaping to make freeways nice places to be. Please remember to send us your freeway design art by 5 p.m. Wednesday, May 13, so we can include it in our slideshow of everyone's work.

If you've finished your design and are looking to do something else fun, some creative people I work with have come up with a word search and a construction zone maze. Depending on your age and interests, you can print one or both by clicking the images below.

You'll find these and other activities at the ADOT Kids home page, azdot.gov/ADOTKids. 

Have fun, everyone!

South Mountain Freeway word search:

Work zone maze:

Driving through construction zones may not be the most enjoyable experience, but at least there's the promise of an improvement to come.

So we understand if it's might be a little confusing if you don't see anyone while driving through a work zone. We're often asked on ADOT's social media accounts why drivers don't see work happening when lanes are closed in a particular work zone.

About 90 percent of the time, when drivers don't see work happening, it's because crews are doing the lion's share of the construction when traffic is lighter, according to Jesse Gutierrez, ADOT's deputy state engineer for operations. Many times the work itself is being done at night, when additional lanes may close and crews and equipment will be in the construction zone. 

"Typically we are coming back within hours to do work," Gutierrez said.

As we told you about in a blog last year, ADOT schedules what work it can at night. However, there are several factors, such as noise or the type of work being done, that won't let construction occur at night. When work is scheduled for daylight hours, contractors will often work in shifts that avoid high-traffic times of days simply because it's safer when less people are on the road.

Gutierrez said that another reason is that construction work might have only a certain window of time when it can be done. In cases where work will temporarily impact a utility, such a power line, water main or even a canal, construction has to be scheduled when it will affect the fewest people.

There few other reasons, like construction halting several days before and after a major holiday, but they are less common, Gutierrez said.

But if construction is happening at other times, then why are there still cones and barricades up when you are driving home? The answer comes down to safety. ADOT follows certain standards to protect the driving public while construction is happening. Part of that is physically separating traffic from any potentional hazards in the work zone. And if a lane needs to be closed, a long taper is needed to help traffic move over long before it reaches where the work is happening. 

The goal is always to compete projects as quickly and safely as possible, even if there is no one around to see it.

On March 4, Governor Doug Ducey and others gathered in Nogales to break ground for a project improving State Route 189, the 3.75-mile state highway connecting the Mariposa Port of Entry and Interstate 19. This is a big deal not just for Nogales and Santa Cruz County but for all of Arizona and beyond, as SR 189 carries a large share of the winter produce consumed in the United States and plays a big role in the state economy. 

The Mariposa Port of Entry saw about $24.1 billion in imports and exports in 2018, and up to 1,800 commercial trucks a day use SR 189 during winter months.

The video at right allows you to experience the excitement of the groundbreaking ceremony and learn more about the $134 million in improvements coming to SR 189, known locally as Mariposa Road. These include flyover ramps connecting with the interstate that will eliminate the need for commercial trucks to stop as many as three times between I-19 and the international border.

With the flyover ramps connecting with SR 189 west of Frank Reed Road, the improvements will enhance safety for students of nearby Nogales High School. The project also includes a new roundabout at Target Range Road and improved drainage and traffic signals. 

Construction is expected to begin in April and take about 18 months to complete. You can learn more about SR 189 improvements and their value to Arizona's economy at azdot.gov/SR189. 

Ninety-eight years ago, the Tombstone Epitaph's front page shared "about the best announcement that has come to Cochise County on road work for some time."

The State Highway Department's top engineer, Thomas Maddock, informed the newspaper that work had been approved to extend an existing 8.5 miles of highway between Tombstone and Fairbank, a stretch completed in 1919, west to the Santa Cruz County line. That was part of plans to create a highway linking Tombstone and Nogales along the path that today carries State Route 82. The story said Engineer Al Jenkins was moving a construction crew to Cochise County.

"Telephone advices received later from Mr. Jenkins from Patagonia were to the effect that he was breaking camp and loading all equipment today, ready to move tomorrow, and will begin throwing dirt Tuesday," it said. 

That was Tuesday, Feb. 7, 1922, so today is the anniversary of that dirt-throwing.

Various accounts from the time say this highway was an offshoot of the cross-country Bankhead Highway, which followed the path of what was then US 80 (now State Route 80) from the New Mexico line through Douglas, Bisbee, Tombstone and Benson. It then went to Tucson, Phoenix and eventually Yuma. According to the Arizona Republican, one goal of a Tombstone-Nogales highway was linking the Bankhead Highway with Mexico's highway between Mexico City and Nogales. That would create a valuable international connection for what was billed at the time as the USA's only all-weather coast-to-coast route. 

The map at top right, from a mid-1920s Highway Department report, shows the route of the Tombstone-Nogales highway. 

For the work creating 15 miles of highway between Fairbank and the Santa Cruz County line, grading with heavy equipment was to start at both ends, the Tombstone Epitaph said. The article spends quite a bit of time explaining the three camps being established to make this happen, including one at a ranch midway "for equipment, stock and other material." The interactive map at lower right allows desktop and tablet users to learn more about sites important to this construction project.

"The news that work will be started will bring joy to both Santa Cruz and Cochise county road advocates," the article said. 

A 1924 biennial report from the Highway Department's state engineer said crews had completed 52.3 miles, from Tombstone to Patagonia, of what would eventually be a 74.3-mile gravel highway. It noted that the 25 miles in Cochise County had been turned over to the maintenance department by construction crews. 

"This highway throughout is constructed along modern lines and is in excellent condition and repair," the report said. "With possibly the exception of a few miles in Cochise County, which should be sanded where the caliche surface during wet weather is inclined to become somewhat slick, only general maintenance is necessary."

Now State Route 82, the highway passes through gorgeous country, as you can see through these Google Street View images from Fairbank, Sonoita, Patagonia and approaching Nogales. You'll notice that today's highway is no longer gravel, so that somewhat slick caliche surface has long since been taken care of.

Next time I drive it, I'll think about the day almost a century ago when Al Jenkins' crew began "throwing dirt" to make this beautiful highway a reality.