I know this is kind of old, but I just found out as of October 1, 2015, ADOT has actually made some changes to its Engineering District boundaries.
- Most of the Prescott District was merged with the Kingman District, with the Camp Verde and Payson Maintenance Units being moved to the Flagstaff District.
- The Globe District has been eliminated, with the northern half becoming part of the Holbrook District, and the southern half becoming part of the Safford District.
- The Winslow Maintenance Unit was moved from the Holbrook District to the Flagstaff District.
- The Saint David Maintenance Unit was moved from the Safford District to the Tucson District.
- Boundaries for the Phoenix and Yuma Districts have been expanded slightly.
Those are going to be some pretty big engineering districts, sounds like ADOT got hit with some cut-backs.
Note that the City of Maricopa was realigned from the Tucson District (now officially known as the South Central District) to the Phoenix District (now officially known as the Central District). The boundary passes just south of Maricopa. My guess the reason is because the City of Maricopa chose to join the Maricopa Association of Governments (MAG, which is actually the MPO for Phoenix/Maricopa County) over the Sun Corridor MPO (Casa Grande's MPO), thus it makes more sense to align them with Phoenix as far as funding and maintenance goes since they are part of the same MPO.
My district lost Benson and Sierra Vista, and gained Globe. From a planning standpoint, I suppose this makes sense as the Southeast district is now composed of small towns, agriculture and mining, with a handful of mountain highways. It's very rural in nature.
Sierra Vista, as far as planning needs are concerned, has more urban needs in common with Tucson, as will Benson in about 25 years if the large developments planned in the area pan out.
I always thought it was neat that the Safford District had a handful of "Big City" road features like dual turn lanes at SR 90 and SR 92/Fry Blvd. But we just got our first Red Turn Arrow in Safford about a month ago, along with a right turn arrow that lights up when cross traffic has a left turn arrow.... not to mention the urban diamond interchange at I-10 and Rex Allen Drive in Willcox some 10 years ago. So I guess we're movin' on up!