ADOT Research Center

Numbering Arizona's highways

Numbering Arizona's highways


Numbering Arizona's highways

Numbering Arizona's highways

March 5, 2014

What’s in a name, or a number for that matter? You’d still be able to “get your kicks” even if it wasn’t called Route 66…

But it turns out there actually is meaning behind our state’s highway names. That’s what we learned after turning to page 39 of “Arizona’s Transportation History,” a publication produced last year by the ADOT Research Center that takes a look back (way back to the 1400s) at the state’s highway system.

Here’s a passage directly from the report that explains how and why Arizona’s highways were numbered.

It was in late 1925 that the final step was taken toward setting up a modern highway network in Arizona. Following guidelines developed by the American Association of State Highway Officials (in 1973 the AASHO changed its name to the American Association of State Highway and Transportation Officials – AASHTO) and approved by the Bureau of Public Roads, the highway department assigned each of Arizona’s highways a unique number, with the east-west roads getting even numbers and the north-south roads getting odd numbers.

This map of Arizona’s state and U.S. highways can be found in the Arizona Transportation History report. It was published just after the first highway numbers were assigned. Some of the numbers were later changed.

The National Old Trails Highway, which ran from Lupton to Topock via Holbrook, Winslow, Flagstaff, Ash Fork, and Kingman, was initially designated U.S. Route 60. Soon thereafter it was renumbered U.S. Route 66. Under that number, as the celebrated Route 66 connecting Chicago with Los Angeles, this highway would become Arizona’s most famous stretch of roadway. The Springerville-Holbrook alternate route of the National Old Trails Highway was numbered U.S. Route 70, a designation it would lose in the mid-1930s, when it was renumbered U.S. Route 260.

The Lee/Bankhead/Dixie Overland highways, which ran from Rodeo, New Mexico, to Yuma via Bisbee, Benson, Tucson, Florence, Phoenix, and Gila Bend, was numbered U.S. Route 80. This had been Arizona’s first complete east-west highway, and now, as part of U.S. Route 80, it made up one section of the Southwest’s most important highway, connecting El Paso with Tucson, Phoenix, and Los Angeles.

The northern branch of the Lee Highway, from Duncan, on the New Mexico border, to Phoenix via Globe, was designated U.S. Route 180; later, in the mid-1930s, it was renumbered U.S. Route 70.

Parts of the Grand Canyon–Nogales Highway were designated U.S. Route 380 (south of Tucson) and U.S. Route 280 (between Phoenix and Ash Fork), while a new highway from Flagstaff to Fredonia, on the Utah border, was designated U.S. Route 89. Soon the 380 and 280 numbers were dropped, and the entire highway from Nogales to Fredonia was made part of U.S. Route 89, which eventually would connect Mexico and Canada.

Arizona also began numbering its own highways. The first numbered state highways were State Route 79, from Prescott to Jerome; State Route 87, from Mesa to Casa Grande; State Route 88, which was the Apache Trail; State Route 83, from Vail to Sonoita; and State Route 82, from Nogales to Tombstone via Patagonia and Sonoita. Several of these highways still bear the same numbers today.

Another interesting note we found in the report has to do with the now-familiar symbols for U.S. and Arizona highways. According to the report, just as Arizona routes were being given unique numbers, the state also adopted the “shield” symbol for federal highways and the Arizona-shaped signs for state highways.

More from the report on the signs we now know today as the norm…

The Arizona Highway Department also began putting up standardized road signs, under a system devised by the AASHO and approved by the federal government. These included octagons for stop signs, black-on-yellow diamonds for warning signs, and circles for railroad signs. As part of this signing program, all previous signs put up by the private highway associations and local governments were taken down.

For more on Arizona’s transportation history, check out the report for yourself. You can also get a glimpse of our state’s past by revisiting our “From the ADOT Archives” blog posts.

ADOT report examines relationship between land use and congestion

ADOT report examines relationship between land use and congestion


ADOT report examines relationship between land use and congestion

ADOT report examines relationship between land use and congestion

October 30, 2012


Land Use and Traffic Congestion Study Cover

The "Land Use and Traffic Congestion

ADOT’s Research Center recently published an interesting new report that takes a closer look at the relationships among land use, transportation and gridlock…

The report, “Land Use and Traffic Congestion”, makes a few important discoveries, including:

  • Residents of some higher-density neighborhoods in the Phoenix metropolitan area drive substantially less than similar residents who live in lower-density and automobile-dependent suburban neighborhoods. The study finds that urban dwellers drive about a third fewer daily miles than their suburban counterparts
  • Roadways in more compact, mixed and multimodal communities tend to be less congested. This is due to fewer vehicle trips, particularly for local errands, more travel by walking or the use of public transit, and because the more connected street networks offer more route options, so traffic is less concentrated on a few urban arterials. 
  • The report also shows that compact, mixed-use, pedestrian-friendly development has significant transportation benefits for communities  that’s important to note. Since most land use decisions happen at the local level, ADOT is stepping forward to build strong land use partnerships by engaging our local and regional partners and stakeholders, so decisions are made proactively and collaboratively. 

Moving forward…
This research report helps ADOT identify and define challenges and solutions surrounding land use. It also serves as a tool as ADOT moves forward to develop and implement Smart Transportation policies that will allow the agency to meet Arizona’s growing transportation needs.

“ADOT, like many state departments of transportation, recognizes the relationship between transportation and land use decisions,” said ADOT Director John Halikowski. “Through a concentrated effort to better link transportation planning and land use planning, we can support economic growth and create jobs, meet demand for quality of life and livability in communities, be better stewards of our natural environment, and manage our financial resources more efficiently.”

ADOT's Approved Product List helps save time

ADOT's Approved Product List helps save time


ADOT's Approved Product List helps save time

ADOT's Approved Product List helps save time

November 8, 2011

Among the APL's many products, several sign products are on the list.

You might say each ADOT road construction project is a sum of its parts …

After all, you can’t build a road or a bridge without materials like aggregate, cement, and other structural materials.

But did you know each of those components must adhere to certain specifications? Some of the requirements are spelled out at a state level, while others are determined by the Federal Highway Administration and American Association of State Highway and Transportation Officials.

Because project engineers and contractors don’t have the time to evaluate all the materials and traffic control products on the market, the ADOT Research Center’s Product Evaluation Program is designed to assist them.

ADOT’s Research Center maintains the “approved product list” (APL), which contains products found suitable for use in highway construction in Arizona. The list is updated every month and contains products that have been evaluated and found acceptable by ADOT.

The approved products list is NOT comprehensive. It’s not an endorsement list, either.

Contractors can and do use products not on the list … those products just may require proof of third-party testing before it’s OK’d for use on a project.

How it works …

Vendors submit an application to the Product Evaluation Program manager. (Until recently, applications were mailed to ADOT. Now vendors email their applications and work is being completed to automate the process even more.)

Once an application is received, the product is assigned a product identification number, and then it may be assigned to an evaluator if a category exists for the product.

It is evaluated and the results are presented to one of two committees …

There’s the Traffic Control Product Evaluation Committee and the Materials Product Evaluation Committee. Each committee meets every three months and is responsible for approving or disapproving products on the APL.

If approved, a product will typically remain on the APL for about five years before it must be recertified. If product changes have occurred, then ADOT may reevaluate the product or request a new application if the product has changed significantly.

Product Evaluation Program Manager Stephanie Huang says it can take at least three to six months for a product to be evaluated and submitted to committee. According to Huang, 145 products have been assigned product identification numbers so far this year, which is up from 117 in 2010.

ADOT library is focused on transportation research

ADOT library is focused on transportation research


ADOT library is focused on transportation research

ADOT library is focused on transportation research

October 25, 2011

Librarian Dale Steele oversees the collection at the ADOT Research Center Library. The library recently moved into a space previously occupied by the Roadrunner Cafe, a cafeteria for ADOT employees. The cafe moved out, but the sign stayed behind!

The ADOT Research Center Library might not carry any best-sellers, but where else are you going to find a title like, “Benefits of high volume fly ash: new concrete mixtures provide financial, environmental and performance gains”?

That study, published by the Federal Highway Administration in 2010, is on the shelves alongside thousands of publications – all of them focused on transportation planning and engineering.

Established in 1989 as part of the ADOT Research Center, the library is open to ADOT employees, transportation faculty in Arizona universities and others with an interest in transportation.

The goal is to keep a collection that not only preserves the information ADOT produces, but also includes reports from other state DOTs, transportation boards, federal transportation agencies and professional societies.

Librarian Dale Steele says having all this research and information on hand is valuable to ADOT employees who work each day on the state’s transportation system … it gives them recent data and a look at what other transportation departments are doing.

“Managing information is important to providing Arizona with a more efficient transportation system,” Steele says. “The library is a key part of getting current information to decision-makers.”

Steele searches online databases for the material and secures copies for the ADOT Research Center Library. He’ll often secure copies of ADOT reports for the state library and Arizona State University’s library.

Most states are starting to produce more of their information electronically, which means Steele doesn’t get a physical copy of the work. However, he does assist ADOT employees with literature searches and can access several online works.

“What we can do is find out what is out there and try to get it,” he said.

The ADOT library collection consists of nearly 30,000 books, magazines, videos and CDs! Here are a few more examples of titles lining the shelves …

* “Effects of yellow rectangular rapid-flashing beacons on yielding at multilane uncontrolled crosswalks,” Federal Highway Administration, 2010

* “Clarkdale transportation study,” ADOT, 2011

* “Roundabouts: an informational guide; second edition,” National Cooperative Highway Research Program, 2010

Research Center guides ADOT toward transportation innovation

Research Center guides ADOT toward transportation innovation


Research Center guides ADOT toward transportation innovation

Research Center guides ADOT toward transportation innovation

August 8, 2011

The ADOT Research Center studies ways to improve transportation in Arizona.

Much has changed since ADOT got its start in 1927.

Back then, the agency was known as the Arizona State Highway Department and roads certainly were built a little differently. Methods, materials and technology have changed so much since then.

Amazingly, they’re still evolving today …

ADOT keeps up with transportation advancements through research. The ADOT Research Center oversees that research, which is aimed at improving all aspects of transportation in the state and beyond.

But, don’t think the studies and research produced by this team just sit on a shelf once completed.

The information generated by ADOT’s Research Center focuses on evaluating new materials and methods. ADOT’s researchers look at developing design and analysis techniques and study the underlying causes of transportation problems.

In other words, this research leads to better methods, innovative practices and new ways of doing things, giving Arizonans a better value when it comes to transportation!

To get an idea of how this research ends up influencing the way ADOT operates, take a look at the seven emphasis areas within the ADOT Research Center :

  • The Environment emphasis explores the interaction between transportation and the environment. Studies from this discipline look at air quality policy, emissions reduction, transportation-generated noise, wildlife and other environmental topics.
  • The Maintenance emphasis researches how to enhance the maintenance and operation of roadways. A recent study is evaluating the effects of snowplow and deicing chemicals on rubberized asphalt pavements.
  • Materials and Construction studies scrutinize the products and methods used in constructing roads. One study from this emphasis provided research into the noise reduction properties of rubberized asphalt.
  • Research within the Structures emphasis area aims to apply effective modern technology and resources to enhance the implementation of bridge management systems, including the repair of over-stressed bridge decks.
  • Traffic and Safety research not only investigates engineering principles to help solve traffic problems, but it often takes into account the psychology and habits of drivers. Research projects have included a study on seat belt usage in Arizona.
  • Intelligent Transportation Systems analyzes ways to integrate advanced communication technologies into transportation infrastructure. Study topics have included freeway ramp metering, electronic message signs and emerging technology.
  • The Planning and Administration discipline looks to our transportation future – how ADOT can best meet travelers’ needs as the population grows, our society evolves and technology offers more options. This emphasis also addresses organizational issues within ADOT. One ongoing study within this emphasis will report on how new media can bolster ADOT’s community outreach.

There’s much more to learn about this team. Visit the Research Center’s webpage for additional information and stay tuned. In the future we’ll blog about the ADOT Research Center ’s library and product evaluation program.