The U.S. state of Arizona's State Routes are usually abbreviated as SR.
History
The Arizona State Highway system was introduced on September 9, 1927, by the State Highway Commission (formed on August 11 of the same year). It incorporated the new federal aid system and also the U.S. Highway system. The 1927 plan included 27 state routes, most of which were simply dirt roads. Until 1942, the state route marker signs contained a Native American swastika that were used by Navajos, but were removed after the U.S.'s entry into World War II against Nazi Germany which had a reversed swastika as its emblem and became strongly negatively associated with the Nazis.
The modern system was introduced and adopted in the 1950s.
Designations and nomenclatures
The Arizona Department of Transportation (ADOT) internally recognizes Interstate Highways, U.S. Highways and Arizona Highways as all being separate types of highway designations. State highways within Arizona are referred to as Arizona State Routes or State Routes, with the prefix "SR" being used for abbreviations. ADOT also recognizes seven different types of suffixed routes for the U.S. Highways and State Routes. The recognized suffixes consist of the following with "(Number)" filling in for a numeric designation:
- Alternate (A) – Referred to as "State Route (Number)A" and abbreviated as "SR (Number)A".
- Business Route (B) – Referred to as "State Business Route (Number)" and abbreviated as "SR (Number)B" or "SR (Number) Bus.".
- Loop Route (L) – Referred to as "State Loop Route (Number)" and abbreviated as "SR (Number)L". Despite often having "Loop" within their titles, SR 101, SR 202 and SR 303 are not considered "Loop Routes" by ADOT, nor are Interstate Business Loops.
- Spur (S) – Referred to as "State Route (Number) Spur" and abbreviated as "SR (Number)S" or "SR (Number) Spur".
- Truck (T) – Referred to as "State Route (Number) Truck" and abbreviated as "SR (Number) Truck".
- Temporary (X) – Publicly referred to as "State Route (Number) Temporary" or "State Route (Number)T" and abbreviated "SR (Number)T". Internally referred to as "State Route (Number)X" and abbreviated "SR (Number)X". Suffixed routes for Interstates are a different story. Although the suffixed routes are signed with Interstate green Business shields, they are recognized by ADOT as suffixed State Routes. In the field, Interstate 10 business routes are signed as Interstate 10 Business Loop or Interstate 10 Business Spur, while they are referred to by ADOT as "State Business Route 10" (SR 10B) and "State Route 10 Spur" (SR 10 Spur). The same principle applies with business routes for all other Interstates in Arizona. As the system grew and expanded throughout the decades, more and more routes were added. A notable development came in 1932, when the first 3 digit spur route was added, State Route 287, a spur of Route 87. As the system continued to grow and evolve, some routes were decommissioned, and their numbers were re-used for future highways, as due to the limitations, limited numbers were available. As US routes began being decommissioned due to the rise of the Interstate Highway System, old alignments were often added to the state route system, keeping the number of the old US Highway, as a state route, all falling in the 60-99 range. As the system started to run out of numbers, more and more spur routes began being added to the system, which sometimes did not connect to their true parent, but rather, "in the vicinity" of the route. In 1974, the last 60-99 number was added to the system, State Route 98. The passage of Proposition 300 brought proper freeways to the valley, spelling the end of the state route system, since as mentioned above, state route freeways follow their own numbering rules, and State Route 143 in 1985 marked the first non-spur route to fall outside of the 60-99 system. The true end of the system occurred one year later, when State Route 238 (a non-freeway) was added, given the number seemingly at random, rather than "94" as proposed. Since 98 was added in 1974, all routes added to the system have either been freeways, spurs, small three-digit stubs, or de-commissioned US routes. Since the program's inception in 1927, all numbers between 60 and 99 were used by at least one State or US Route, aside from 94.