B. The superior court may review by certiorari the action of the board establishing, opening, relocating, altering, vacating or abandoning state highways.

Also:

The current process for abandoning or transferring routes from the state highway system is featured in Figure 2 on the following page. The process begins with a determination that the route should no longer be a part of the system. There are four ways in which this can occur:
1. The route is classified as LOD 5. [89A is LOD 3]
2. A bypass or parallel route is constructed making the route non-essential for the state system.
3. The DEs or other state official determines that the route no longer serves a state function.
4. A local government desires to take over the route.

74 roads are listed as meeting criteria for turnback and therefore listed as priorities for transfer. 89A south of the Y is not on the list.

http://www.azdot.gov/mpd/priority_programming/pdf/study/rtranstudy.pdf

As for local government desiring to take over the route, that means the people, will now have the opportunity to make that decision by way of casting their votes. Unless “Guest” has inside information, that route will continue to function as a State Highway under the ownership of the City of Sedona. Or is a Bypass in the works of which we aren’t aware?

Secondly, AZ State law supports ADOT “abandoning” routes after it has paved them and given the city or county four years advance notice. The law requires that the Transportation Board abandon routes, to the underlying city, or county agency, or to another agency identified in the intergovernmental agreement that implements the transfer (ARS 28-304 and 28-7201-28-7815).

Requirements for abandonment of a state roadway are defined in ARS 28-7209. Section 28-304 stipulates that; 1) vacating or abandonment must be in cooperation with the affected jurisdiction, 2) fully recognizes the financial and administrative impacts of the changes on that jurisdiction, 3) the abandonment or transfer notice must occur four years in advance if not waived by mutual agreement, 4) the pavement before the abandonment occurs “shall be in such condition that additional surface treatment and major maintenance of the highway would not be required for at least five years” unless this requirement is waived by the board and the affected jurisdiction.

Finally, since the City has been negotiating with ADOT for the past two plus years no doubt that could be interpreted by a court that the City has been “cooperating” with ADOT.