AUBURN — The school department’s head of maintenance, custodial services and transportation will retire from his role effective Friday, according to Superintendent Cornelia Brown.

The city will begin managing the school district’s maintenance, custodial and transportation operations under a new contract Monday, which a city news release said would be more efficient and cost effective.

“Our goal is to provide the safest, most efficient transportation possible, and to ensure clean, well-maintained facilities and playing fields for the children and families of Auburn,” Public Works Director Denis D’Auteuil said. “Staff and residents should know that we have full confidence that this will be a successful, positive change. We are looking forward to these dedicated employees joining our exceptional team.”

The retirement of Director of Student Support Services William “Billy” Hunter follows an investigation from the Maine State Police Motor Vehicle Inspection Unit on Feb. 8, which found that Auburn’s school buses were not properly inspected by Lance’s Auto And Truck Repair in Monmouth.

The district’s buses were inspected by Allegiance Trucks in Auburn after the discovery. Buses resumed operation three days after the improper inspections were found.

Hunter was placed on administrative leave while the district investigated the problem.

“(Hunter) would have been able to come back had he chosen to do that,” Brown said Wednesday. “It was his decision to retire.”

Reached by phone, Hunter confirmed he has retired from the school district, but declined to provide further details.

Hunter was hired as a custodian by the district 28 years ago in 1993 and assumed the role of director of Student Support Services in 1999.

Transportation has been a significant challenge for the district this year, and bus routes have often been canceled because of a shortage of drivers. Resignations from the district have outnumbered new hires.

Last week, Brown presented a transportation action plan to the School Committee, which included a bus driver training program.

“I look forward to collaborating with the city of Auburn to improve our transportation services to families,” Brown said in a news release. “I appreciate their patience as we have worked through some difficult challenges recently.”