Bridges Engineering and Construction

Understanding what’s underneath a road makes a lasting road

Understanding what’s underneath a road makes a lasting road


Understanding what’s underneath a road makes a lasting road

Understanding what’s underneath a road makes a lasting road

By Kathy Cline / ADOT Communications
April 6, 2024
Liquid limit device used in ADOT's T89 test

Constructing roads requires plenty of planning: Determining the location, design and materials are all important. One key element that might go unnoticed by many, though, is gaining an understanding of the soil and ground upon which the road will be built.

For that, we introduce you to ADOT’s Soils and Aggregates Lab.

“Soil tests are done before every project,” said David Coronado, a transportation engineering specialist. “The tests help engineers to understand the soil's properties, stability, and bearing capacity. It also helps engineers choose the best materials to use to ensure a durable and long lasting structure and roadway performance.”

Prior to the construction phase of a project, ADOT’s Soils and Aggregates Lab runs tests on soil samples taken from the project area. These tests can involve very simple procedures, like rolling a ball of clay back and forth by hand until it crumbles, which is essentially rolling out the moisture until it loses its integrity and can no longer hold together. Other tests are more complicated, like the aforementioned counterpart involving mixing a fine grained soil and using a mechanical device which must adhere to a set of specifications and criteria.

One common soil test is T89, a counterpart to T90, which together determine the soil's plasticity. According to the American Association of Highway Transportation Officials(AASHTO) technical regulations, a technician mixes a soil sample with 8-10/15-20 milliliters of distilled water until it is completely absorbed, further adding 1-3 millimeters until it becomes viscous. The resulting mixture is then placed into the brass dish of a liquid-limit device and spread carefully to conform to the dish's shape while meeting the regulated 10 millimeter thickness criteria.

A groove is cut vertically into the soil separating two sides, with a clear visible brass dividing line. The liquid-limit device is turned on, subjecting the dish to shocks, which is lifting it 10 millimeters in height and dropping it onto the base causing both sides from the split to close in on each other. Once both sides touch at approximately half of an inch at the required 25 shocks, a soil sample is taken by performing a horizontal cut across the soil where both sides meet, placing it in a glass jar and recording the wet weight before putting it in the oven to dry until achieving a constant weight. After the dry weight is recorded, the calculation for the percent moisture is done.

Coronado says Arizona has diverse soil types, including sandy and gravelly soils. “The Phoenix metropolitan area mostly consists of sandy soils, as well as a mixture of sand, silt, and clay,” he says. “In northern Arizona, such as Flagstaff, heavy clays are more prevalent.”

As for what type of soil is best to build roads on: “Ideally, free-draining but with enough clay for cohesion and stabilization, but not so high a clay content that the water is prevented from draining,” Coronado said. “Granular soils with fines are best. High clay materials affect drainage and are highly absorbent, which also leads to issues with swelling and shrinkage thus affecting the road's integrity and are not suitable to build on. Also, very silty soils are not ideal as they can be prone to collapse when water is introduced.”

So next time you see the dirt beside the road, know it was thoroughly tested before that road was built.



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In Florence, we’re building a bridge that’s designed to move

In Florence, we’re building a bridge that’s designed to move


In Florence, we’re building a bridge that’s designed to move

In Florence, we’re building a bridge that’s designed to move

By Garin Groff / ADOT Communications
April 7, 2022

When ADOT builds a new bridge, our top priority is to make sure the gigantic mass of steel and concrete stays right where we build it.

But that won’t be the case with a new bridge we’re constructing on State Route 79 in Florence, because this bridge is designed to move.

Or more precisely, slide. 

This new bridge’s mobile nature will be only temporary, however, as part of an innovative method of constructing a new bridge by assembling the new structure’s components next to the old bridge and then sliding them into place.

The process begins by constructing new bridge piers in the bed of the Gila River. The piers will be extra wide so the new structure’s components can be built in halves on either side of the old bridge. Once the new segments are complete, crews will tear out the old bridge and slide each half of the new structure where the existing bridge now stands.

ADOT has slid new bridges into the place of old ones before, including a 2020 project to replace the Fourth Street bridge over Interstate 40 in Flagstaff.

By sliding a bridge into place, ADOT can keep traffic moving with minimal delays during construction. Both lanes of traffic will remain open during the SR 79 project, except for two weekends when the bridge halves are slid into place. On both weekends, a temporary traffic signal will restrict traffic to one lane in each direction.

The existing bridge was built in 1957-58 and has reached the end of its useful life. When ADOT began planning for a replacement, engineers had several options for its construction. 

One common method involves building the new bridge next to the old one, which was the case when ADOT replaced the Pinto Creek bridge on US 60 between Globe and Miami. That option was ruled out for the Florence bridge project because of the additional cost to buy right-of-way and shift the road to the new structure. 

Another approach is replacing the bridge one half at a time, which is how ADOT replaced the SR 77 bridge in Winkelman. That option would have meant only one lane of traffic would remain open during the project, which would have led to excessive delays because SR 79 carries significantly more traffic than the highway through Winkelman.

No matter what method ADOT chooses to replace a bridge, our goal is to maintain a safe and reliable transportation system while minimizing delays for motorists. In the case of the project in Florence, drivers should look for a reduced speed limit in the work zone and watch for traffic alerts when the bridge slides require two weekends of lane restrictions. 

Learn more about the project and stay up to date by checking out the SR 79 bridge replacement project page

From professor to bridge designer

From professor to bridge designer


From professor to bridge designer

From professor to bridge designer

Kathy Cline/ADOT Communications
September 21, 2021

Struts, blueprints and girders filled her daydreams ... and Afrin Hossain has turned them into reality as one of ADOT's newest bridge designers!

New ADOT bridge designer Afrin HossainBorn in Bangladesh, Hossain's interest in bridge design came early, thanks to her father who served as a civil engineer in the country's roadway department.

"Seeing my father work," Hossaid said, "seeing the blueprints he brought home, and seeing his shoe filled with asphalt after a busy construction day is what inspired me to get my undergraduate degree in structural engineering at Bangladesh University of Engineering and Technology." While there, Hossain studied structures like the Golden Gate Bridge in San Francisco. "The more I got to know about these structures the more I fascinated I became with them," she said.

Another influence and inspiration was fellow countryman and high-rise-design innovator Fazlur Rahman Khan.  Khan pioneered many improvements in skyscraper and high-rise design. He designed the former Sears Tower in Chicago. He was also an early trailblazer in computer-aided design, as well. "As a Bangladeshi, I also wanted to design and build just like him," Hossain said.

Hossain eventually earned a doctorate while in Canada in structural engineering and presented her work and research in many countries. The travel gave Hossain opportunities to see structures such as the Eiffel Tower in France and the Astoria-Megler Bridge in Oregon. It was the U.S. highways and bridges, however, that inspired her the most. 

"Living in the States for approximately three years, helped me gain a new appreciation for roadway infrastructures," she said. "Here, in the U.S., roadways, bridges (George Washington, Benjamin Franklin, Golden Gate, other bridges in Portland, and Pittsburgh etc.), tunnels (Holland, Lincoln, Chesapeake Beach etc.), retaining walls, noise bearing walls, ramps, interchanges, nested exits - all just amazed me."

Hossain decided to settle in Arizona, and began teaching other eager students at Northern Arizona University about engineering and working with materials like steel, concrete and timber. Her enthusiasm and teaching experience helped Hossain land a job at ADOT ‒ despite the pandemic and other challenges.

What's next? Hossain says she's looking forward to designing smart hybrid bridges incorporating concrete, steel and timber. "Whenever, I drive on Arizona roadways, I always pay a close attention to infrastructure details," she says.

"I am passionate about designing irrespective of the kind of the structure: building, bridges, roadways, foundations, etc. I envision myself not only just designing but also seeing my design be built."

Pinto Creek Bridge opens a new chapter in Arizona history

Pinto Creek Bridge opens a new chapter in Arizona history


Pinto Creek Bridge opens a new chapter in Arizona history

Pinto Creek Bridge opens a new chapter in Arizona history

By Kim Larsen / ADOT Communications
August 12, 2021

American engineer and educator James Kip Finch said “The engineer has been, and is, a maker of history.”

That can definitely be said of the engineers and team members working on the Pinto Creek Bridge project as they are creating a replacement for a 72-year-old bridge, located on US 60 about six miles west of Miami, to keep a southern Arizona community moving.

When the project began in 2012, many factors came into play, including addressing historic preservation with the Federal Highway Administration and bridge aesthetics with the U.S. Forest Service. Another consideration was environmental impact, which led to the mitigation and conservation of the Arizona Hedgehog Cactus in the canyon.

An interesting development was the discovery of a mine adit, which is basically a prospector’s tunnel, a consideration during the original construction in the 1940s. The team did 3D modeling of the foundation excavation limits to determine the type of foundation that would reduce any risk due to the mine adit.

ADOT used value engineering to develop improvements to the construction feasibility review and efficiency of the bridge, saving about $1.5 million.

“Adjustments were made to the foundations and column reinforcing for efficiency and constructibility,” Bridge Designer Rafe Davis explained. “A bid alternate was developed in the plans and specifications which provided the contractor flexibility.”

The bridge is now about 73% complete. The girder lift took place in April, but it was an involved process

“The girders took more than three months to fabricate, not including the time for required submittals and to prepare the structural steel shop drawings,” Project Supervisor Kim Vanvolkinburg said. “Once girder delivery to the project began, it took them about six weeks to set and splice all the girders and cross frames. The contractor brought in multiple cranes, and had to move them several times due to the logistics of working adjacent to the existing highway and within the canyon below.”

The projected completion date is January 2022.

“This will likely adjust some as there is a lot of work yet to be completed,” Vanvolkinburg said. “Hopefully, the weather will cooperate.”

Read more about the bridge project and progress in the ADOT Blog. Discover photos of the project and the girder lift on Flickr

It's an old road to Post Office Deck Bridge renovations

It's an old road to Post Office Deck Bridge renovations


It's an old road to Post Office Deck Bridge renovations

It's an old road to Post Office Deck Bridge renovations

By Laurie Merrill / ADOT Communications
August 9, 2021

On State Route 73 in the Fort Apache Reservation, alongside the North Fork White River in some of the prettiest country around, ADOT is in the process of replacing an old bridge deck. 

By the standards of the region, the Post Office Canyon Bridge, built in 1968, isn't quite a senior citizen at 53 years. But if it could talk, it would tell you the top song that year was "Hey Jude," by The Beatles, minimum wage was $1.60 an hour and a Big Mac was 49 cents.  

The single span, steel girder bridge rises more than a mile above Post Office Canyon at 5,912 feet. 

It is located nearly half-way down an 11-mile stretch of SR 73, between Indian Pine near State Route 260 and the Alchesay National Fish Hatchery, that was designated in 1993 as the White River Scenic Road. The route is a U-shaped loop, about 40 miles long with one end on US 60 north of Carrizo and the other near Indian Pine and State Route 260.

According to the state-published Arizona Memory Project, SR 73 started out as little more than a foot trail: 

“With the establishment of a military camp in 1870 that would be renamed Fort Apache in 1879, the development of rough trails into passable packed-earth roads became necessary. In 1929, the old trail that would become SR 73 allowed horse-riding soldiers and mule-drawn freight wagons to reach the remote garrison from both the north and the south.“ 

The Post Office Canyon Bridge was probably named after the canyon it crosses, the Post Office Canyon, said the ADOT engineer who is overseeing the deck replacement, Navaphan Viboolmate (Noon) of ADOT’s Bridge Design Section. 

Before 1968, an earlier bridge across the canyon had a deck built from timber, Viboolmate said. It was torn down to make way for the current bridge.

“It was an open design,” he said. “Driving on it you could see side rails and cross rails.” 

Located in Navajo County between mileposts 348 and 349, the bridge sits on a section of SR 73 that is classified as a Rural Major Collector Road. 

“It connects to local communities, including Fort Apache, Whiteriver and Cedar Creek,” Viboolmate said. “It connects State Route 260 and US 60.” 

By ADOT engineering measurements, the bridge is safe, but because ADOT specifications and standards have evolved, it’s time to replace the current deck with reinforced concrete 8-inches thick and to replace deck drains, deck joints and bridge barrier transitions, among a host of other improvements. The project will reconstruct and significantly extend the life of the bridge

The project is in full swing and crews are demolishing and replacing the old decks.

According to the project website, the following restrictions are in place from 6 a.m to 6 p.m. seven days a week through September:

  • SR 73 is narrowed to one lane of alternating north- and southbound travel near the Post Office Canyon Bridge (mileposts 348-349).
  • A temporary traffic signal helps drivers travel through the construction area.
  • 12-foot vehicle width restriction in the work zone.
  • Reduced speed limit in the work zone.

When you cross the newly refurbished span, you now know you will be one mile high, on the White River Scenic Road and a Rural Major Collector Road --  and on a passage whose history began in the 1800s.  

For these trainees, the road to engineering starts with ADOT

For these trainees, the road to engineering starts with ADOT


For these trainees, the road to engineering starts with ADOT

For these trainees, the road to engineering starts with ADOT

By Laurie Merrill / ADOT Communications
July 30, 2021

When it comes to hiring promising young engineers for the Arizona Department of Transportation, there’s probably no bigger cheerleader than Candee Samora.

After all, Samora, ADOT’s Engineer-in-Training and Intern Program manager, has landed her dream job and brings her considerable enthusiasm to work every day.

“I’ve wanted to work for state government since I was 12 years old,” she said. “And I wouldn’t want to be anywhere else but ADOT.”

She gets to work with young engineers in training, who also bring considerable enthusiasm to their roles.

“They bring excitement, new blood, new ideas,” Samora said. “They are fabulous.”

In interviews, engineers-in-training (EIT) extolled the virtues of a program that provides so much education and training in so many areas and allows them to see the role of engineering in major projects from start to finish.

“Working with projects so large-scale and critical for the traveling public has been very interesting to see and be a part of every step of the way,” said Brandy Wagoner, recently assigned to Deer Valley Construction.

In the video above, we interviewed Jimmy Naujokaitis, an ADOT resident engineer in Phoenix, who is an enthusiastic graduate of the EIT program. 

"Being in the EIT program allows you to get integrated into ADOT culture and see how things are run," he said. 

Like a lot of future engineers, when he was a kid he excelled in math, science and Legos! 

ADOT can choose from a wide pool of applicants since the agency no longer requires a Fundamentals of Engineering certificate for eligibility.

Recently, the criterion shifted and trainees are required to pass the exam during the 2-year-program, Samora said.

ADOT also sets the trainees on the path for passing their Professional Engineer license, which is considered the highest standard of competence. 

They receive an apprentice-style education that provides hands-on experience and side-by-side mentoring in such disciplines as roadway design, environmental planning, multimodal planning and materials lab. Every few months, they rotate between Roadway Design, Project Management and outlying rural construction projects.

We recently asked a few engineers in training about what they like best about ADOT’s EIT program. Here are some of the highlights:

Wagoner, also quoted above, added that she likes seeing “first-hand how massive transportation projects travel from a vision, to a project, to each design team and how they work together to complete the design, to bid, and finally to construction.”

And the work environment is excellent.

“The atmosphere of being an ADOT EIT is so welcoming, encouraging and creates an environment that I have always felt comfortable and supported in,” Wagoner said.

Diana Palma, recently assigned to the Transportation Systems Management and Operations (TSMO) Division, enjoys learning first-hand about each unit’s responsibilities and the potential for career progression within the state. 

She also listed “the opportunity to apply principles of the Arizona Management System to everyday activities and to see the positive impact on practices.”

Babak Dehghani called the program “an amazing introduction into the professional world.”

He enjoys seeing how ADOT brings construction projects from beginning to finish and how, by working under registered professionals, he has gained the training and experience to become registered as a professional engineer.

Steven Neher, recently assigned to the Multimodal Planning Division, listed the opportunity to work with many different groups, field visits, chances to grow and career development.

“All of these reasons culminate in this grand chance to better myself as a person, an engineer, and a professional, laying the foundation for techniques and habits that can help serve me to my benefit for years to come,” Neher said. “Every road starts somewhere and I'm glad mine began with ADOT.”

Watch us make a new bridge, and maybe a future bridge builder

Watch us make a new bridge, and maybe a future bridge builder


Watch us make a new bridge, and maybe a future bridge builder

Watch us make a new bridge, and maybe a future bridge builder

By Garin Groff / ADOT Communications
May 24, 2021

If you drove by Interstate 10 in far east Tucson on a recent Monday night, you couldn’t have overlooked a massive boom pumping concrete onto the new Houghton Road overpass.

But we wanted to share something you couldn’t have seen while zipping through the area: A little father-daughter bonding at what was dad’s office that night.

Meet Jeremy Moore, the Assistant District Engineer for ADOT’s Southcentral District, and his 11-year-old daughter, Kailey (both featured in the video and photo on this page!). 

Moore oversees the interchange reconstruction project and figured this busy work site was a perfect place for his daughter, who is eyeing a career in some kind of engineering or architecture. Kailey loves structures, so what could be better than watching part of a 12-hour, overnight operation to pour 1,000 cubic yards of concrete that now form the bridge’s future driving surface.

Kailey is a sixth grader at St. Joseph Catholic School in Tucson who has a passion for Taekwondo – she’s a second-degree black belt – and loves engineering, technology, science and math.

Thankfully for Kailey, there was a lot of math to soak in!

Her father shares a few interesting numbers on all that concrete. It’s:

  • 1,626 tons
  • 803 cubic yards
  • held together with 123 tons of reinforcing steel
  • forming a structure that’s 245 feet long, 125 feet wide and 8.5 inches thick

If Kailey ever decides to build something like a bridge, she got the perfect lesson under the stars that Monday night.

As to the project and what it means to drivers, this concrete pour represents a milestone. The entire bridge deck was poured in just one night, which means crews can plan for shifting traffic onto that new structure later this summer. That in turn allows us to demolish the old two-lane Houghton Road bridge and complete the ramps on the east side of the interchange.

And a few more numbers to finish with: The $24.4 million project is expected to be complete in about 7 months – at the end of 2021. Expect some nighttime and weekend lane restrictions, which could lead to delays of about 15 minutes.

How a bridge comes to life

How a bridge comes to life


How a bridge comes to life

How a bridge comes to life

By Kathy Cline / ADOT Communications
May 5, 2021

Leslie Canyon Bridge near Douglas, AZA bridge is often an awesome sight to behold: Thick pillars, massive abutments, maybe lots of shiny steel tubing soaring into the sky above a canyon. Or, it could be as simple as a concrete structure crossing a small wash (like the Lowell Arch Bridge near Bisbee).

You may have wondered, if you've passed by or driven on one recently: How did this thing get designed and built?

Wonder no more: Bill Downes, an ADOT design engineer, is here to help explain the process. He says a bridge design engineer must consider three very important points:

  1. Geometry: "How long does the bridge need to be, what does it go over and how high is it," said Downes. "The bridge must be high enough to allow traffic or flood water to pass under it."
  2. The number of spans: "Essentially how many piers will be needed. Where can piers be placed is also a major factor in this decision. You cannot place piers in a roadway. Where is the roadway below the bridge, and where will it be in the future?"
  3. Traffic: "This is not much of a problem on a new bridge on a new roadway, but it is very important on a bridge replacement. Can the new bridge be built next to the existing bridge and the roadway moved over? Can the road be closed/detoured during construction? Often traffic must continue even while trying to build a new bridge."

In addition to all of these, Downes says, the engineer must also take into account utilities near the proposed site; how and where construction crews will access the site and store their equipment; and whether accelerated bridge construction (ABC) methods can be used.

"Although ABC reduces traffic disruptions, they generally cost more and require special planning," he says.

The topography and soil of the proposed bridge site are also important.

"What type of soil is in the area, and what types of foundations can hold up the bridge. Can shallow foundations like a spread footing be used, or are deep foundations such as drilled shafts required?"

Then comes the review.

"As each item is looked at, it may change the choices made earlier," says Downes. "For example, the ability to ship girders to the worksite may change how many piers you will need to have."

After all the data gathering and review, it's time to start designing!

"This is the point where we start the math to determine how strong each bridge element needs to be," he says.

Although no one can predict future traffic patterns, engineers must allow for that, too.

"Bridges historically were designed to last 50 years," he says. "Generally we now design for a 75-year life and many will be expected to continue to carry traffic for over 100 years with only little maintenance or rehabilitation." 

Once the design is completed and approved, Downes says, plans must be made for contractors; and once a contractor is chosen, the bridge design engineer will need to work with the contractor throughout the construction process.

The most important point of all?

"Although bridges are beautiful things they don’t exist in isolation," Downes says. "Building a bridge cannot be accomplished without a great deal of coordination and work with roadway, geotechnical, traffic, district, right-of-way, utility, environmental, material, drainage and other engineers."

ADOT Kids: Here's how to have 'engineer as a career!'

ADOT Kids: Here's how to have 'engineer as a career!'


ADOT Kids: Here's how to have 'engineer as a career!'

ADOT Kids: Here's how to have 'engineer as a career!'

By David Rookhuyzen / ADOT Communications
February 23, 2021

We love engineers!

But do you know that there are many different types of engineers? Just at ADOT we have many different kinds who look at everything from the best way to get cars over a bridge to the water and power lines that go underground. 

If you've ever thought about being an engineer, here are some of the options available to you!

And once you have read about all the different types of engineers, click on the photo to have your parents download our seek-and-find activity to match them with the type of work they do!

Civil Engineers:

If you’ve got the inclination to draw, design, problem solve and create order, you might want to be a civil engineer. Civil engineers uses computer-aided design and drafting to prepare the technical drawings used to build freeways, bridges, and more. Civil engineering deals with the design, construction, and maintenance of the physical and naturally built environment. This includes public works such as roads, bridges, canals, dams, airports, sewage systems, pipelines as well as structural components of buildings and railways.

ADOT has many specific kinds of civil engineers. These include:

  • Geotechnical engineers, whose knowledge of soils and rocks are important to building roads and bridges.
  • Drainage engineers with expertise in designing for flooding and erosion control.
  • Environmental engineers with expertise in minimizing the negative impacts to the environment while constructing and maintaining transportation features.

Civil engineering also includes what we are going to look at next: roadway, traffic and bridge engineers. 

Roadway, Bridge and Traffic Engineers:

Roadway, Bridge and Traffic engineers use mathematics and science to determine where or how to build new highways and to make existing highways better.

  • Roadway engineers work with many other types of engineers and together they make plans for construction to make the highways. Roadway engineers design the geometric parts of a road such as widths, curves and slopes.  They also design road safety hardware like guardrails.
  • Bridge engineers use computer programs to design the bridges that carry cars and trucks over waterways, rivers, washes, railroads and other roadways.  
  • Traffic engineers design the signs, pavement markings and roadway lighting that help make the highways safe to drive on and help people understand where they need to go. They also design traffic control plans used to help traffic move safely through a work zone.

Resident Engineers:

Resident engineers work in ADOT district offices around the state and make sure contractors who build the projects follow the design plans. They also help resolve challenges and find solutions while the project is being constructed.

Survey Engineers and Surveyors:

Before a designer can prepare construction plans for highways, roads and bridges, they need more information about the land they wish to build on.

  • Surveyors use tools to measure and locate features like mountains and rivers that can be used to make topographic maps. Topographic maps detail the “topography” of the land, showing the surface of the earth and features such as hills, rivers and houses. These maps and plans help engineers design highways and bridges. Aerial photography is done by planes or drones taking pictures from the sky. Did you know that George Washington was a surveyor?
  • Survey engineers and surveyors provide engineering surveys and topographic maps to assist designers of ADOT highway projects. They collect and analyze 3-D information about the land, roads and bridges. They use sophisticated equipment such as Global Positioning Systems (GPS), levels and electronic theodolites. Theodolites are special telescopes that help them measure angles while surveying. They then use computers to make 3-D digital drawings for other engineers to use while designing highways. Survey engineers and surveyors also help ADOT’s Right of Way group by performing property surveys. 

Transportation technology engineers:

Transportation technology engineers use computers, electronics, control systems (like traffic lights), communications technologies and management strategies for transportation systems to provide travel information to improve road safety and efficiency. As new transportation technologies emerge, like self-driving vehicles and smart/connected cars, transportation technology engineers are needed to make sure our infrastructure safely accommodates these new transportation trends.

Have you seen the message boards along the freeway? These are types of transportation technology. Technology is also used to calculate the travel times displayed on the boards like how long it will take to get from Phoenix to Tucson based on distance and how fast cars are traveling. If there is a crash on a road and a lane is closed, it will take much longer to get to Tucson from Phoenix. 

Utility and railroad engineers:

Utility and railroad engineers work with utility companies and design engineers to locate underground utilities. Did you know that things like the water, electricity and gas that come into your house are called “utilities?” The pipes and wires that bring these utilities are located underground or strung from large poles. Utility engineers help place all these pipes and wires under the ground or on poles.

When highway projects are happening, utility engineers help locate these utilities and other items that could interfere with construction. They use non-invasive technology and techniques along with carefully controlled excavation methods to provide detailed information on underground features so they can either be avoided or relocated. This process is important to construction workers’ safety, controlling costs and making sure people nearby can still have water and electricity.

ADOT does not have engineers that drive trains but they have engineers to determine what to do when a road and a railroad meet at a crossing or when a bridge goes over or under a railroad. To ensure that trains and cars can travel safely while sometimes crossing paths, utility and railroad engineers ensure the safety of motorists and train operators by using signs, signals and pavement markings.

Engineer as a career

There you have it! There are so many different types of engineers you can grow up to be. But all of them are important in designing and building highways and bridges, not to mention keeping people safe. 

While deciding what kind of engineer you want to be, have fun with the seek-and-find activity! And if you are really interested in being an "engineer-as-a-career," watch for more ADOT Kids videos, blogs and activities running this week for National Engineers Week. And make sure to check out the ADOT Kids website or find #ADOTKids on social media!

From the Director: Inspiring wonder in transportation projects across the state

From the Director: Inspiring wonder in transportation projects across the state


From the Director: Inspiring wonder in transportation projects across the state

From the Director: Inspiring wonder in transportation projects across the state

By John Halikowski / ADOT Director
February 22, 2021

Designing bridges and roads. Surveying land and streams. Improving road safety. Maintaining existing transportation infrastructure. These responsibilities and more reflect the work our engineers perform daily at the Arizona Department of Transportation. Whether you are a bridge, civil, roadway, survey, traffic or transportation technology engineer, your work matters and makes a difference in the communities we serve. Therefore, I am proud to recognize our engineers for National Engineers Week, Feb. 21-27, under the theme “Inspiring Wonder.”

Building a safe and efficient transportation system requires the skills of many talented engineers and support staff. It takes knowledge and teamwork to design and operate a state transportation system. I see the accomplishments our engineers achieve every day. It is especially rewarding when our teams are recognized, both locally and nationally, for projects that serve the traveling public. Examples are the wrong-way driver detection and dust storm detection systems, and the one-year-old Loop 202 South Mountain Freeway.

Having the right skill set to build bridges and roads, and implement safety measures requires an interest in STEM (Science, Technology, Engineering, Math) education. It is never too early to pique the interest of children in the field of engineering and inspire a world of wonder.

Our national award-winning ADOT Kids program is an example of teamwork and the work of our engineers. We created ADOT Kids in an effort to educate children about transportation and to keep it fun. From learning how snowplows operate, to building a bridge and decorating our roadways with unique designs, to creating highway safety messages and Keeping Arizona Grand, ADOT Kids has been a huge hit with children, parents and educators. Our ADOT engineers and employees have enlightened the community by serving as subject matter experts in answering questions from children. 

I have the most deep respect for the engineering community. I congratulate our engineers on this special week of recognition. They do indeed inspire wonder in our communities and are worthy of us saying ‘thank you’ for the work they do.