Former Arizona Supreme Court Chief Justice Ruth V. McGregor will serve as an independent observer in Friday's labor negotiations between First Transit and ATU 1433.
Earlier this month, union and bus company officials signed a temporary agreement to keep Valley Metro buses in the Phoenix metropolitan area running until at least midnight July 30.
The last scheduled negotiation date is on Friday.
"Chief Justice McGregor has a track record of success," said Phoenix Mayor Greg Stanton. "I have full confidence that with her help we can keep the buses running for the people of our region."
First Transit, Valley Metro's East Valley bus operator, and ATU 1433, the bus operator's union, have been in labor negotiations since the first of the year to define their collective bargaining agreement consisting of operator wages, benefits and work rules.
The union represents about 400 bus drivers.
A potential bus drivers' strike would shut down nearly half of Valley Metro's routes primarily in Mesa, Tempe, Chandler, Gilbert and into Phoenix and Scottsdale.
Copyright 2013 CBS 5 (KPHO Broadcasting Corporation). All rights reserved.