Arizona Road Network

By | October 13, 2022

Arizona is very sparsely populated, and does not have a dense road network. A number of US Highways and Interstate Highways cross the state. The biggest crowds are concentrated around Phoenix and Tucson. Arizona is an important transit state for the state of California, and the Los Angeles metropolitan area in particular.

Road management

The state highway authority is the Arizona Department of Transportation, abbreviated ADOT or AZDOT. ADOT manages 9,907 kilometers of road, 14,965 kilometers of carriageway and 34,417 kilometers of lane. ADOT has its origins in the Arizona Highway Department, which was established in 1912 when Arizona became a state. The current name was adopted in 1974.

  • Bittranslators: State overview of Arizona, including geography, economy, population and history as well as introduction to major cities of Arizona.

Interstate Highways

To the south, Interstate 8 runs as an east-west route between Yuma and Casa Grande, while Interstate 10 is a somewhat longer east-west route from Ehrenberg via Phoenix and Tucson to the New Mexico border at San Simon. Interstate 15 runs through an isolated stretch of northwest Arizona. Interstate 17 is a north-south route in the central part of the state, between Phoenix and Flagstaff. Interstate 19 runs from Tucson to the Mexican border at Nogales. Interstate 40 forms an east-west route in the north of the state, from Topock via Kingman and Flagstaff to Lupton on the border with New Mexico.

There are no 3-digit Interstates in the state, which is striking given the presence of two major metropolitan areas; Phoenix and Tucson. Tucson is the largest US city with only 2 highways; the I-10 and I-19. Phoenix is the largest US city without 3-digit Interstates.

  • Deluxesurveillance: Nickname of Arizona as The Grand Canyon State. Also covers geography, history, economy, politics and administration of the state.

US Highways

The secondary road network is formed by a few US Highways, of which the US 93 to Las Vegas is the most important. There are only 2 roads that cross the Colorado River near the Grand Canyon, so northwestern Arizona is quite isolated from the rest of the state. The roads are long and can become dull over time due to the lack of traffic. Some US Highways handle less than 2,000 vehicles per day. A network of State Routes supplements the road network, but most of them have no major through importance. The only State Routes that are highways are in the Phoenix metropolitan area.

State Routes

In the state of Arizona, they are referred to as a “state route” and commonly abbreviated as “SR.” Arizona’s road network is quite thin and the through roads are usually numbered as a US Highway or Interstate Highway. As a result, there are few state routes of more than 150 kilometers in length. The numbering runs from 1 to 587 but most of the numbers are skipped. There are only two state routes numbered less than 50 (of which the SR-30 is planned). State routes can be developed as freeways, these are located in the Phoenix metropolitan area. Important are the SR-101 and SR-202 which are also known as a loop.

The Arizona State Highway system was introduced in 1927 and at the time included 27 state highways, most of which were unpaved. The road number plates originally included a mirrored swastika (swastika), a common symbol of Native Americans at the time. In 1942 the number plate was changed. The current road numbering system was introduced in the 1950s. About 30 routes have since been cancelled.

Nearly all state routes in Arizona are paved, with the biggest exceptions being State Route 88 and State Route 288. State Route 366 to the Mount Graham International Observatory is Arizona’s highest state route at 3,191 feet. Several state trails run at more than 2,000 feet, especially in eastern and northern Arizona.

Road numbering

The first road numbering was introduced in 1927. The current numbering system was introduced in the 1950s. Low numbers of the state routes have never been in use. The main routes were already formed by US Highways from 1927. The two-digit state routes are generally the most important, the three-digit state routes are often an offshoot of the two-digit ones, although not in all cases. Some route numbers are derived from former US Highways. Several state routes lead to dead ends in the wilderness, to lakes, recreation areas, National Monuments, mountain peaks or astronomical observatories. Some three-digit numbers make up long routes, most notably State Route 260 and State Route 264.



Before the mid-19th century, Arizona actually had no roads, the “roads” that existed were actually trails used by migrants and the US military. The Arizona Territory took the first step in 1877 to build a road, a wagon road between Phoenix and Globe. To this end, $10,000 in road-building bonds was issued, the first road-construction bonds in Arizona. Numerous wagon roads were built across the Arizona countryside in the second half of the 19th century. In 1885, the first bridge in the administration of Arizona Territory was built, a bridge over the Gila River near Florence. In 1886, however, the United States Congress halted bond issuance. Arizona was already over-indebted and unable to build new roads for the next 23 years.

However, the quality of the first road network varied widely from county to county and road to road. Until the early 20th century, there were no paved roads in Arizona, and only one bridge, the one over the Gila River near Florence. In 1910, Arizona had only 204,000 residents and thus little tax revenue to fund a road network that reached all parts of the state. A windfall for Arizona was that there is little precipitation and the dirt and gravel roads often remained passable, in contrast to wetter parts in the United States.

The first state highways

In 1909, the Arizona Territory established a “network” of state highways consisting of only two roads that were primarily paper-based, an east-west route through the south of the state from Yuma through Tucson to the border with New Mexico, and a north-south route from Douglas to the Grand Canyon. Between 1909 and 1912, 233 kilometers of this was constructed, mainly on the north-south route. This was mainly an improved gravel road, elsewhere there were only dirt roads. In 1912, Arizona became a state and the State Highway Department was established with the task of developing Arizona’s highway network. In the first years after ‘statehood’ prisoners were mainly used to build roads. Several bridges were also built during this time. The first roads were built in the 1920s, such as the Phoenix to Tempe road and the Bisbee to Tombstone road, important economic centers of Arizona at the time due to the mining industry. In the early years, the counties spent even more money on roads than the state. In 1913 there were only a few kilometers of modern gravel road, the rest of the road network consisted mainly of poorly constructed dirt roads.

In 1914, the Good Roods Movement emerged in Arizona. At the time, the state had 9,633 miles of road, the 45th largest road network of any state, while Arizona was the fifth largest state. Moreover, not a single road was paved at the time. In 1916 there were already 12,000 cars in Arizona, but not a single paved road. The best roads in Arizona at the time were gravel roads. At that time, some auto trails ran through Arizona. With the Federal Aid Road Act from 1916 federal money became available for roads. After this, Arizona was able to build the first paved roads, the first paved roads in the state were the Bisbee-Douglas Road, the National Old Trails Highway through Flagstaff and Winslow, the Tucson-Florence Highway and the Tucson-Nogales Road. By far the longest paved road in Arizona ran through the Salt River Valley from Mesa to Buckeye, through what is now the Phoenix metropolitan area. Several car trails came together on this route. In 1921, 100 kilometers of this had already been paved with asphalt or concrete.

The US Highways and State Highways

US Highways were introduced in 1926. At the time, numbers US 60, 70, 80, 89, 91, 180, 280, and 380 were assigned in Arizona. At the time, US 80 was the only road that had a longer stretch of asphalt, through Phoenix. Also, US 80 between Tombstone and Douglas was paved, as well as a short stretch of US 280 (current US 93) from Phoenix to halfway through Wickenburg, and US 380 (current I-19) from Tucson a few miles south. Elsewhere the routes were mostly gravel roads, although several longer stretches of the US Highways were still dirt roads.

Later in the 1920s and 1930s, some US Highways were renumbered. US 60 became the famous US 66. US 180 from Phoenix via Globe to the New Mexico border was later renumbered from US 180 to US 70. US 280 and US 380 were north-south routes that later merged into US 89.

With the introduction of the US Highways, the state also began to number the state highways. The first were State Route 79 from Prescott to Jerome, State Route 82 from Nogales to Tombstone, State Route 83 from Vail to Sonoita, State Route 87 from Mesa to Casa Grande, and State Route 88 as the Apache Trail. Several of these routes still have these numbers today. In 1926 Arizona had a network of 3,273 kilometers of state highway, of which 335 kilometers were paved.

In 1928, it was estimated that it would cost $75 million to asphalt the entire network of state highways, an unfeasible amount at the time. As an interim solution, they started with a cheaper solution, by spraying a thin layer of oil on gravel. These ‘oiled roads’ were dust-free and somewhat more comfortable than gravel roads, but had little bearing capacity and did not last long. The road from Tucson to Nogales was the first oiled road in Arizona. After that it went very fast, between 1928 and 1933 more than 1,500 kilometers of road were provided with an oil layer. It could then be claimed that all US Highways were ‘paved’, although in practice this was no more than an oil layer on gravel. In 1933, the last piece of gravel between Phoenix and Tucson also disappeared.

During the economic depression of the 1930s, funding from the New Deal was used to further improve Arizona’s road network. The most important project during this period was the construction of US 60 between Globe and Springerville in the east of the state. This project was completed in 1938, but partly with an oil pavement. Further improvement of the road lasted until 1941. By 1940 much of the main road network had been paved, a huge improvement over 15 years earlier.

A problem from the late 1930s was the low design requirements of the paved roads. Many roads had simply been widened and paved along their historic paths, targeting speeds of 50 to 80 km/h. However, traffic demanded roads that could be driven from 100 to 110 km/h. Many bridges had not yet been built, the passage of the seasonal rivers was flooded during the rainy season. Hardly any road paved before 1934 had modern design requirements. However, the Second World War slowed down the modernization of the road network. Almost no money was allowed to be spent on goals other than warfare.

After World War II, Arizona’s population began to grow strongly, especially around Phoenix. Traffic on the roads increased rapidly, and what was once the pride of Arizona, the oiled roads, were from then on considered suitable only for secondary roads. From the second half of the 1940s, large-scale improvement projects were carried out on the roads in Arizona. The oil surfacing was replaced by modern asphalt and roads were given a more optimal alignment, with wider lanes that could easily reach 100 km/h. In 1957, the modern US 93 opened between Wickenburg and Kingman, which was to become the route between the fast-growing cities of Phoenix and Las Vegas. US 180 opened in 1960as a new access road to the Grand Canyon from Flagstaff.

The freeway era

Arizona had only about 1 million inhabitants when the Interstate Highway system was created in 1956. Phoenix was a city of just 100,000 people at the time, and Tucson was the largest city at the time with about 200,000 people. The first highway opened in 1955, a stretch of what would later become I-10 west of Sierra Vista in the east of the state. This stretch was less than 2 kilometers long.

Construction of the Interstate Highways in Arizona began in 1957. At the time, there were hardly any four-lane highways in the state, but the Interstate Highway system and the growth of the Phoenix area would change that. The first Interstate Highway was 2 miles from I-17 in Phoenix, which opened in 1957, and included the first grade-separated intersection in Arizona with Grand Avenue. By 1961, 250 kilometers of Interstate Highway had already been opened, especially considering the fact that 25 years earlier there were hardly any paved roads in the state. Most of the long-haul highways were built in Arizona during the 1960s. Construction was fairly straightforward, due to the vast uninhabited desert areas and the limited number of works of art required.

The Interstate Highways would mainly replace US Highways. For example, I-10 was partly constructed over US 80, and I-40 largely over US 66. A problem for the villages on the route was that they were largely dependent on passers-by for their existence. Many small businesses such as hotels, restaurants and gas stations depended on long-haul traffic for much of their income. These places were often the reason why the construction of the bypasses of Interstate Highways was the last to be completed. Controversial at the time, however, was the construction of Interstate 10 west of Phoenix, which cut off part of US 60. US 60 makes a detour through Wickenburg, while I-10 is built directly west on what’s called the ‘Brenda Cutoff’.

In northern Arizona, there was strong opposition to plans to build I-40 out of town. When US 66 was built west of Kingman in 1952 on a more southerly route, the village of Oatman lost almost all revenue. Other places along US 66 such as Holbrook, Winslow, Flagstaff, Williams, Ash Fork and Seligman feared the same would happen to them with the construction of I-40. It was a conflict between local interests in the villages and national interests of long-distance traffic between the major cities. In the end, it was even decided to build I-40 directly between Kingman and Seligman, bypassing some villages along old US 66 at a greater distance.

By 1967, half of the planned Interstate Highway network in Arizona was already open, with the majority of the remaining part under construction or established. By 1972, 79% of Interstates were complete, and when the “Brenda Cutoff” of I-10 opened west of Phoenix, more than 1,000 miles (1,600 kilometers) of Interstate Highways had been completed. In 1971, the first interchange between two freeways in Arizona opened, between I-10 and US 60 in Tempe. Also in 1973 was the first Interstate Highway in Arizona completed, the I-15 through the famous Virgin River Gorge in the extreme northwest of Arizona. In 1978, I-8 and I-17 were completed along their entire route.

In addition to the construction of the Interstate Highways at the time, many other state highways were also modernized in the 1950s, 1960s, and 1970s, especially those of interest to tourists, such as nearly every road northbound from Phoenix. from Arizona. In 1962, US 160 opened to traffic between Tuba City and Kayenta in the northeast of the state, providing tourists with easy access to the Navajo National Monument, Navajo Nation, and Monument Valley. With the construction of several roads, Flagstaff became the dominant traffic hub in northern Arizona. Also in 1962, newly constructed US 191 opened between Springerville and Clifton in the eastern part of the state. In the early 1960s, the US 89. was also between Flagstaff and the Arizona border. This was necessary for the construction of the Glen Canyon Dam at Page. In the mid-1960s, US 60 between Phoenix and Wickenburg was widened to 2×2 lanes. In 1969, the first single lane passing lanes were also built in Arizona. In 1974, State Route 260 opened between Payson and Show Low, right through the White Mountains.

The Interstate Highway network in Arizona was largely completed in the mid-1970s, but there were still a number of missing links until roughly the mid-1980s. In 1978, there were still four missing sections of I-40 around the villages that delayed construction for a long time. In 1984, the last bypass of I-40 opened, around Williams. A controversial project was to construct I-10 through downtown Phoenix on a 100-foot (30-meter) overpass. Planning for this started as early as the 1960s and the project was approved in 1970, but there was strong opposition to the viaduct. This section was later constructed in a tunnel and opened to traffic in 1990.

Plans were underway for a large network of freeways in the Phoenix area as early as the 1950s, including a 1960 road plan that closely resembles what was eventually built, but implementation was delayed for years. The Phoenix area grew rapidly during that time, sometimes exceeding 50,000 residents per year. In the 1980s, the construction of a regional highway network around Phoenix became more concrete and financing was also established, an increase in the sales tax in Maricopa County. The plan was to build 375 kilometers of new freeways in and around Phoenix using $8.5 billion in tax revenues. A large part of this motorway network was constructed between 1990 and 2015. A ring structure was constructed, with Loop 101 around Phoenix and Loop 202 around the eastern suburbs. The first to be completed was the Superstition Freeway (US 60) through Mesa in 1991. In 2001 Loop 101 was completed and in 2003 the Piestewa Freeway (formerly Squaw Peak Parkway) was completed. In 2006-2008, the final portions of Loop 202 opened around Phoenix’s eastern suburbs, completing the regional highway plan. However, Phoenix continued to grow, and work began on Loop 303, a new west bypass of Phoenix. It opened to traffic in phases between 2011 and 2014.


The focus in Arizona is primarily on the highway network of the Phoenix area and the development of Interstate 11, which should in any case replace US 93 to Nevada, but may also pass west of Phoenix, with a possible starting point at the border. with Mexico in Nogales, although I-11 south of Casa Grande is unlikely to run parallel to I-10 and I-19.

A new freeway, the South Mountain Freeway ( Loop 202 ), is being built around the southwest side of Phoenix. This is Phoenix’s largest highway project in the coming years. There were also plans to widen the so-called ‘Broadway Curve’ of I-10 between Phoenix and Tempe to more than 20 lanes, but this project has been postponed following the 2009 financial crisis. There are also plans for new freeways south of Phoenix., and possibly a second connection between Phoenix and Tucson.

Grand Canyon

The Grand Canyon is the most famous point in the state of Arizona and is visited by 5 million tourists every year. Contrary to popular belief, the Grand Canyon isn’t exactly a day trip from Los Angeles. It is approximately an 8 hour drive one way. The Grand Canyon is generally inaccessible wilderness. Only two points can be reached by road, the South Rim, and the less visited North Rim. The South Rim is via State Route 64 and US 180 accessible, the nearest larger town is Flagstaff. It is over an hour’s drive from I-40 at Williams. The South Rim is basically accessible all year round, but in winter the driving conditions are sometimes bad. State Route 64 runs directly along the chasms at 6 points. The North Rim is much less frequented, with approximately 7,000 vehicles driving daily to the South Rim, but only 100 to the North Rim on State Route 67. The North Rim is often inaccessible in winter due to snowfall. A visit to the South Rim in one day cannot be combined with the North Rim, although the two points are only 17 kilometers apart, the distance by road is almost 350 kilometers.


Arizona is primarily a state of long-haul travelers, with most of the congestion around downtown Phoenix. In Tucson there are no regional highways, here the urban arterials are sometimes congested. Some highways such as I-40 run very high, at more than 2,000 meters where strong winds can occur that can be a problem for truck traffic.

Arizona Road Network