Thomas McKernan has retired as chief executive and been elected chairman of Costa Mesa-based Automobile Club of Southern California.

The non-profit mutual benefit corporation has promoted Robert Bouttier from president and chief operating officer to the chief executive’s position.

The Auto Club is the largest member of the AAA federation of motor clubs, offering insurance, travel and financial products and services along with roadside assistance throughout Southern California and other regions of the U.S.

McKernan’s career with the club has spanned 46 years, 21 of them as chief executive. He started in 1966 as a service representative at a Pasadena branch. He moved up to chief financial officer in 1985, and onto executive vice president in 1990. He became president and chief executive in 1991.

McKernan played a key role in driving the organization’s growth, helping increase membership in Southern California to more than 6 million members from 2.6 million in 1991. More than half of Southern California households are now Auto Club members.

McKernan oversaw the acquisitions of AAA clubs in Texas, New Mexico and Hawaii shortly after he became chief executive.

He will serve as a director on the national AAA board, and vice chair of its AAA Foundation for Traffic Safety alongside his duties as chairman of the Auto Club.

Bouttier counts 37 years with the Auto Club, beginning as an insurance claims representative and moving up to management and executive positions.