EDITOR'S NOTE: During National Engineers Week, which calls attention to the importance of engineering and career opportunities in engineering, blog posts are featuring different aspects of engineering at ADOT.

By Caroline Carpenter / ADOT Communications

ADOT engineers design and execute projects, ensure the quality of materials used in pavement, rebar, concrete and more, protect Arizona's $20 billion-plus investment in state highways through preventive maintenance, plan for traffic needs and perform other tasks critical to offering a reliable transportation system.

These creative women and men constantly come up with ingenious ways to meet challenges. On this Thursday of National Engineers Week, let's throw back to some of the engineering innovations we've featured of late.

Foam Injection

To fix a slight dip in the pavement on the Loop 101 Pima Freeway, ADOT engineers decided to use a product that injects foam beneath pavement and avoids having to tear up road surface. Deep foam injection stabilizes the soil, is cost-effective and takes much less time than a more involved project. The video below explains this technique and its benefits.

Straddle Bent Work

Straddle Bents

If you've driven past Loop 202 South Mountain Freeway interchange construction in the West Valley, you've seen straddle bents constructed over Interstate 10 near 59th Avenue. These structures will eventually support flyover ramps. The straddle bent, which straddles lanes of traffic, is an alternative when a typical one-column pier carrying a ramp would need to be in the middle of an existing roadway. This Flickr slideshow has more photos of straddle bents and other highlights from our interchange construction project. And here's an Art of Transportation blog post celebrating the straddle bent.

Temp bridge 87

Temporary bridges

Did you hear about the new bridge you'll never drive? Engineers are using a temporary bridge to reduce traffic impacts as we build a new I-10 interchange with State Route 87 near Picacho. This bridge will only be used by construction vehicles working on the project and will save about 60,000 trips from a materials pit to the work site because it's built to handle large loads. Engineers used a similar idea during a project that upgraded I-10 bridges at Craycroft Road in Tucson, with a temporary bridge maintaining traffic flow and reducing delays.

Prefab bridge

In March 2017, a novel construction technique using prefabricated components allowed ADOT to build a bridge in 96 hours, greatly reducing the traffic impacts from such a large project. Over a long weekend, a 110-foot bridge went up over the Sacramento Wash along Oatman Highway a mile north of Interstate 40 in northwestern Arizona. The video below offers an accelerated look at this accelerated project.

EDITOR'S NOTE: During National Engineers Week, which calls attention to the importance of engineering and career opportunities in engineering, blog posts are featuring different aspects of engineering at ADOT.

By Steve Elliott / ADOT Communications

To explain her role as an ADOT materials engineer, Julie Kliewer suggests thinking about the parts and pieces that go into anything.

“Your house, the sidewalk, the road you drive on every day – it’s all engineered, and it’s all made up of materials,” she says.

As ADOT’s State Construction and Materials Engineer, Kliewer leads a group whose duties include ensuring that quality materials go into roadways, bridges and other parts of Arizona’s highway system. The materials laboratories she directs evaluate everything from the rocks (also known as aggregate) used in asphaltic concrete to the reflective beads used in paints that stripe roadways to the bolts that help hold bridges together to the metal in sign posts.

The photo at right shows a Universal Hydraulic Testing Machine, which the Structural Materials Team uses to evaluate rebar.

While some ADOT engineers focus on design, others on construction and others on maintenance, materials engineers are involved in each of those phases, Kliewer notes.

In the design phase for a new highway, for example, that includes understanding the makeup of the earth beneath the roadway and the pavement that should be put on top of it. During construction, materials engineers make sure the mix of raw materials used in pavement is designed and delivered properly for that area’s conditions, including the temperatures. Later, materials engineers test how the pavement is performing and make sure materials used to maintain it meet specifications.

Kliewer, shown in the photo at top leading aspiring engineers on a project tour, has a Ph.D. from Oregon State University in civil engineering with a specialty in materials, along with minors in geotechnical engineering and numerical methods. The title of her dissertation explains why she’s often referred to around ADOT as having a “Ph.D. in pavement”: Development of Performance-based Test Procedures for Asphalt Mixtures.

While working with pavement is just one of the duties handled by ADOT materials engineers, it's among the most visible to the public, as ADOT's main asset is the thousands of miles of road surface in the state highway system.

If you want a challenge as an engineer with an interest in materials and pavement, try working in a state with many highways exposed to relentless heat and sun and others at high altitudes seeing dozens of freezes and thaws throughout the winter, along with snow and snowplowing.

For materials engineers dealing with pavement, one challenge is writing specifications that get the right pavement mix and good quality for a given area.

“It’s not a matter of just throwing some aggregate and asphalt together,” she says. “It’s a balancing act.”

In asphaltic concrete, asphalt holds together the aggregate that supports the load. One of the things materials engineers look for in a mix is voids, or airspace. If there are too many voids, the pavement won’t last as long as it should. If there aren’t enough voids, it won’t be as stable as it could be. The photo at right shows a Hamburg Wheel Tracker, which ADOT's Pavement Materials Testing group uses it to evaluate asphalt mixes.

In addition to designing the best pavement mix for a given location, ADOT materials engineers test how the road surface will oxidize and growing stiffer over time. That stiffening, accentuated by Arizona’s dry climate and abundant sunshine, contributes to cracks that are addressed with substances evaluated by ADOT’s materials engineers.

Kliewer’s path to materials engineering began in high school, when she couldn’t decide whether to be an engineer or a forester. She was able to do both at Oregon State University, earning bachelor’s degrees in forest engineering and civil engineering but finding that materials classes struck her fancy.

“It just fit me,” she says.

After two years with the Oregon Department of Transportation, working mostly in materials research, she returned to Oregon State University to teach surveying and geotechnical engineering in the College of Forestry. While teaching, she earned a master’s in forest engineering and her doctorate in civil engineering.

The reward of materials engineering, Kliewer says, is figuring out how things fit together, whether it’s in pavement, bridge girders, concrete culverts or anything else making up the highway system.

“If you like solving those kinds of puzzles, it’s a really rewarding career,” she says.

EDITOR'S NOTE: During National Engineers Week, which calls attention to the importance of engineering and career opportunities in engineering, blog posts are featuring different aspects of engineering at ADOT.

By Tom Herrmann / ADOT Communications

Ever played Sim City? The game that has been amusing millions since 1989 lets you design a city from the buildings to the utilities to the roads. Perhaps the greatest challenge: keeping traffic flowing smoothly so workers and customers can get in and out of the city to keep the economy going.

James Gomes

What you really need to succeed – in Sim City or in a real community like Pima County – is someone like James Gomes, traffic engineer for the Arizona Department of Transportation’s South Central District, based in Tucson.

One of the roles of a traffic engineer is keeping traffic moving as smoothly as possible in every direction. It’s not enough to keep traffic moving along Oracle Road (State Route 77, shown above) north of the Rillito River; he has to avoid changes that would hinder traffic flow on the east-west streets that cross Oracle. Another consideration: Traffic patterns are different during the morning rush than they are in the evening.

Traffic engineers can’t control everything, including new construction that affects traffic volumes. Whatever they do needs to be coordinated with other jurisdictions, such as the city of Tucson, Pima County and the Pima Association of Governments.

So how do traffic engineers in each of ADOT’s seven districts accomplish all of that?

“There is a long-standing process used to develop traffic signal timing plans and keep traffic moving,” Gomes said. “Typically we study the corridor, collect and analyze traffic counts, and then we develop timing plans using traffic software to simulate traffic flows based on the traffic volumes, speeds and signal spacing.”

On major streets like Oracle, the challenge of those green lights is even greater.

“There is a huge balancing act that is performed during signal synchronization. We could very well synchronize Oracle Road to get the most motorists through the corridor. But if we shift too much green time to the main thoroughfare, then the side streets would suffer a great deal of delay and drivers wouldn’t be happy about that.”

That’s just one part of the job. Traffic engineers manage street lighting and informational signs, determine the need for turn lanes and signals, conduct speed studies, analyze traffic impacts from new development and participate in planning future projects.

The future: greater technology. New networked signal cabinets along Oracle allow drivers to navigate 7 miles with just three stops for traffic signals. Given all the challenges involved in that, it’s a good result.

EDITOR'S NOTE: During National Engineers Week, which calls attention to importance of engineering and career opportunities in engineering, blog posts are calling attention to different aspects of engineering at ADOT.

By Doug Nick / ADOT Communications

You may have seen the bumper sticker that says, “If you can read this, thank a teacher,” and we heartily agree. We’ll even take it a step further and say if you can (safely) read that bumper sticker while driving on a smooth stretch of state highway, thank an engineer.

Engineering is one of those professions that can be taken for granted. But we have lots of engineers at ADOT, and we know they deserve more than just a pat on the back for what they do. It takes a great deal of skill and knowledge to develop and maintain a safe, efficient and modern transportation infrastructure.

For example, imagine for a moment that you’re driving on State Route 87 from Mesa to Payson. If you’ve done this, you know that stretch covers about 4,000 feet in elevation and is challenged by numerous mountains, several rivers and creeks, countless washes, as well as canyons and hordes of bloodthirsty Minotaurs.

OK, that last one isn’t true. We think. But still, it’s an impressive engineering feat.

So we can agree that putting a highway through the mountains is a daunting task, Minotaurs or not, and the engineering needs to be precise.

Even a rather ordinary ribbon of highway, say, I-10 between Phoenix and Tucson, requires a lot of engineering skill. What may look to mere mortals like a flat roadway is really a series of connected pieces that have to drain rainwater, accommodate everything from wide-loads to motorcycles, and must endure the relentless Arizona heat, which we now seem to have 364 days a year. (Winter was Jan. 19 this year; hope you didn’t miss it.)

It’s not all about highways, either. Our engineers play a huge role in our programs for bicycle and pedestrian safety, transit, aviation and rail corridors and a whole lot more.

Yep, they do a lot, and they usually do it without getting much attention, so now is as good a time as any to say thanks.

Happy National Engineers Week, and thank you!

Engineers are kind of a big deal here at ADOT.

You may already realize the role they play when it comes to designing and building the state’s highway system, but they’re responsible for even more than that.

From electrical and computer engineers who work on the systems that keep traffic moving to geotechnical engineers and traffic engineers, many types of engineers are essential to ADOT’s operations. So, when National Engineers Week rolls around each year, we take it as a chance to highlight ADOT engineers and all the work they do...

Today, we’re doing that by looking back at some of our favorite engineering-focused blog posts from this past year:

• Check it out: Loop 101/90th Street bridge time lapse – learn how (and why) engineers lowered a 160-foot bridge that weighs over 1 million pounds
• Truck escape ramps serve important safety role – hear an engineer explain how truck escape ramps work
• Transportation Defined: Bailey Bridge – see this cool structure that is used (and was designed) by engineers
• Months of US 89 repair work is squeezed down to minutes in new time-lapse videos – see the repair of a landslide-damaged stretch of US 89, a project that involved many engineers
• Hell Canyon Bridge replacement project is underway – learn about a project that, like all ADOT projects, relies on the expertise of engineers
• Why we build roundabouts – learn why traffic engineers use roundabouts to solve traffic problems
• 1.8-million-pound oversize load set to move through Arizona – find out how engineering helped to move a really big truck through our state

More about National Engineers Week
Started by the National Society of Professional Engineers in 1951, National Engineers Week (Feb. 21-27) is marked in February each year to call attention to the contributions of engineers while emphasizing the importance of math, science and technical skills. Visit DiscoverE.org for more.

Saying that engineers are an important part of ADOT is really kind of an understatement.

That’s because they’re absolutely essential to ADOT’s operations. Think about it – civil engineers design and build Arizona’s highways and bridges. Geotechnical engineers are crucial on projects like the US 89 landslide repair. Then we’ve got electrical and computer engineers who work on the systems that allow ADOT to monitor traffic conditions and keep drivers updated. Actually, there are all types of engineers who play vital roles here at ADOT.

So, when Engineers Week rolls around each year, it’s definitely an occasion we like to mark…

Not sure what Engineers Week is? It’s happening now (Feb. 22-28) and according to the official Engineers Week site, the week is meant to celebrate how engineers make a difference in the world. It’s also about increasing public dialogue about the need for engineers and bringing engineering to life for kids, educators and parents.

Since engineers play such a critical role here at ADOT, we thought we’d take this opportunity to look back at some of our favorite engineering-focused blog posts.

• ADOT engineers confirm no damage to 'Stack' following Thursday's fire
• Building a Freeway: Moving a Mountain
• 520-ton oversize load slowly makes its way through state
• Geotechnical section plays important role in roadway and structural design
• Components of a plan set
• Engineer in Training tells what she's learned
• State engineer's responsibilities are numerous
• Engineer in Training program offers new graduates the chance for some real world experience at ADOT
• Future female engineers get an up-close look at Loop 303 construction
• ASU Summer Transportation Institute introduces students to engineering

Visit DiscoverE.org for more information about this year’s Engineers Week. And, be sure to stay tuned to the ADOT Blog for future related posts. Let us know in the comments if you have any transportation engineering-related questions that you’d like us to answer.

Today, we bring you a guest blog post from Engineer in Training Elizabeth Weil (you might remember she also recently blogged about the components of a plan set).

In today's post, she describes what she learned and accomplished during her rotation through ADOT’s communications division. You can read more about the EIT program in this 2012 blog post.

By Elizabeth Weil
Transportation Engineering Associate

As an Engineer in Training, I’ve spent the last two months in the Office of Communications, which is a rare choice so I’ve been told. Some of my other rotations were more typical: Contracts and Specifications, Construction, and Traffic Design to name a few.

But one of the benefits of the Engineer in Training program is the ability to find out how everyone works together to build and maintain our roads. And as I have discovered, Communications is an important part of the process.

If you’re wondering, this blog is part of Communications, along with our other forms of social media: Facebook, Twitter, YouTube, etc. So one of my assignments was to write a blog post, and another was to write traffic-related tweets from the Traffic Operations Center. I watched the video-editing process that occurs before our informational videos show up on YouTube. Social media is one way we communicate with the public; we can answer questions, give up-to-date traffic information, or convey information about a project or event.

Another part of the Communications team is the group of people who work with the media, which is how you see us on TV or hear us on the radio. The Public Information Officers taught me about being interviewed; they asked me difficult questions and filmed my answers, which I later had to watch. I assisted with writing two press releases as well.

I had never been to a public meeting before, and I was finally able to attend one. These meetings are a way for the public to voice concerns over aspects of a project or ask questions. I especially wanted to attend a public meeting because it is closely related to what many engineers do, whether the project is in the process of being designed or constructed. And if you’ve ever wondered whether or not somebody answers that project hotline number we advertise, I was given the opportunity to answer some of your questions about road closures and the locations of ongoing projects.

This is the last of my two-month rotations, and I am about to start my final six months of the Engineer in Training program in Roadway Design. I now have a better understanding of what the different groups of ADOT do, especially Communications. I even spent some time learning about how the Adopt-a-Highway program works and the benefits of having volunteers and sponsors clean our highways. The Office of Communications does much more than I ever knew about, and I’m glad I had the opportunity to learn (and practice my writing skills).

Building a road or a bridge without engineers would be just about impossible…

Even if you did somehow manage to construct something without an engineer’s expertise, it likely wouldn’t be very sound or safe. It probably wouldn’t last too long either.

So, yes, engineers are pretty important here at ADOT. Much of what the agency does depends on their skill and know-how.

Engineers are important to other fields besides transportation. In fact, engineers help create a lot of the objects we use every single day.

It’s no wonder, there’s a whole week devoted to them. What, you didn’t know that there’s an “engineers week”? There is and it’s happening right now!

Engineers Week

According to the Engineers Week website, this week is about celebrating how engineers make a difference in our world.

Since engineers play such a critical role here at ADOT, we thought we’d take this opportunity to look back at some of our previous engineering-focused blog posts.

• Demolishing the Pantano Union Pacific Railroad Bridge
• Geotechnical section plays important role in roadway and structural design
• Portion of Loop 303 project now nearly 90 percent complete
• Improvements made to Avenue 3E Bridge in Yuma
• Components of a plan set
• Transportation Defined: Geogrid
• Moving oversize loads requires big effort
• State engineer's responsibilities are numerous
• State Engineer gives her take on the job
• Engineer in Training program offers new graduates the chance for some real world experience at ADOT
• STEM studies are at the forefront of upcoming transportation event
• Future female engineers get an up-close look at Loop 303 construction
• ASU Summer Transportation Institute introduces students to engineering

Engineers are a valuable resource for the ADOT Blog. We quote them, film them and use their knowledge so we can better explain to you many of our more complex transportation topics.

Without the expertise of ADOT’s engineers, this blog just wouldn’t be the resource that it has become over the past three years. We definitely appreciate our engineers, which is why we’re so glad to share today’s guest blog post with you.

It comes from one of ADOT’s Engineers in Training. We blogged about this innovative program back in 2012, but basically EITs follow a structured program working in varied sections within ADOT. Their time is divided into training blocks that last two and four months. A few of the blocks are mandatory and others are selected by the EIT.

Our guest blogger Elizabeth Weil made the choice to rotate through ADOT’s communications division for one of her blocks! Her time here has included learning about the many ways ADOT communicates with the public. Today, she writes about construction plans and explains some of their different components…

By Elizabeth Weil

Transportation Engineering Associate

We draw them, we review them, and we use them during construction, because they tell us what to do. Roadway plans are common around ADOT amongst designers and construction personnel, but you’ve probably never seen them for yourself. Here are just a few things that we include in plan sets.

Pavement structural sections (above) describe the layers of a roadway. In this example, above the subgrade (the ground below the roadway material) goes 5 inches of AB (aggregate base, a specific size of rock), then a layer of AC (asphalt, or “asphaltic concrete”), a tack coat (an adhesive oil used to make layers of asphalt stick to each other), and another layer of AC on top.

A typical section shows (above) which structural sections are used in specific areas. They’re accompanied by station limits (in this case 1086+00.00 to 1089+02.07). Those numbers refer to a specific location in the same way a milepost would. This typical section also gives a distance from the right-of-way line to the centerline of the road, the slope of the roadway, and widths of the lanes and shoulders. This way, we know exactly where the roadway will go and how big it will be. Think of the typical section as a cross-section of the roadway; if you were driving, you’d be moving into or out of the page.

Typical Section

This is just part of a sheet showing the plan view of the roadway (a bird’s-eye view). There is a lot of information on each of these sheets- this section of roadway has a taper (where the width of the roadway changes), guardrail (the numbers in diamonds are pointing at it), and right of way (the dashed lines near the outside). Numbers in the shapes are referring to a summary sheet which I haven’t included in this post, but each summary gives much more information (such as guardrail lengths).

Lastly, if you were wondering, we don’t usually have numbers in red; these screenshots were taken from our drafting guidelines which exist so we can make our plans as consistent as possible to avoid confusion.

According to one dictionary’s definition, engineering is “the art or science of making practical application of the knowledge of pure sciences, as physics or chemistry, as in the construction of engines, bridges, buildings, mines, ships and chemical plants.”

Sure, it’s an accurate description, but do you get any real sense of what an engineer does from reading that?

We didn’t think so.

To learn about engineering, it helps to hear firsthand from the men and women who work in the field.

Recently, a group of high school students from around the state got to do just that…

It was all part of ASU’s Summer Transportation Institute – a program designed to teach future engineers what it takes to make traffic flow in a safe and effective way.

The students traveled across Arizona during the three-week program and experienced everything from bridge-building basics to lessons in space travel and water transportation. They learned on-site at several locations, including the Hoover Dam and ADOT’s Deck Park Tunnel (see video above). At ADOT, the students also learned about engineering survey and photogrammetry, traffic engineering and equipment services.

It’s this direct approach to learning that instructor Dr. Jan Snyder says gets the kids engaged and fired up for a future career in engineering.

“You hear about STEM (Science, Technology, Engineering and Mathematics) … but until recently, the E in STEM was silent,” Dr. Snyder said. “It has become obvious to many of us that really, engineering provides an opportunity to bring the other three aspects of STEM together in a very interesting, enjoyable way.”

The students certainly seemed to agree…

Stefin Nelson, a junior at Kingman High School, said he’s always been interested in engineering and decided to apply for the institute after hearing about it from his biology teacher.

“I didn’t know there were so many different types of engineers,” Nelson said of what he’s learned from the experience.

Liliana Tapia, a senior at Kofa High School, is interested in civil and aeronautical engineering and, like Nelson and many of the other students, said she was surprised to see the numerous options available in engineering.

“It’s been a lot of fun,” Tapia said of the summer institute. “It’s cool to see how many jobs are created by this certain field.”

Aaron Witt, an Arcadia High School senior, already knows what he wants to do after college … he is looking toward a career in road building.

“I’ve really enjoyed it because we’ve gone through so many aspects of engineering. I want to get paid to play in the dirt and I wasn’t sure that was possible,” said Witt, adding that the summer transportation institute showed him it is possible.