(a) A member may retire voluntarily as follows:

(1) At age sixty-five (65), or during any year thereafter until the age of compulsory retirement has been attained, with a minimum of five (5) years of creditable service in the Arkansas State Highway Employees' Retirement System;

(2) At age sixty-two (62), with a minimum of fifteen (15) years of creditable service in the system;

(3) At age sixty (60), with a minimum of twenty (20) years of creditable service in the system; or

(4) Regardless of age, with thirty (30) years of creditable service in the system.

(b)

(1) Any retired member who has creditable service with the Arkansas State Highway and Transportation Department or the Arkansas Department of Transportation for more than thirty-five (35) years and who is not receiving benefits based on his or her actual creditable service time, on February 27, 1991, shall have his or her annuity adjusted at that time.

(2) The adjustment shall be equivalent to the retirant's original annuity, adjusted for actual service time and subsequent cost-of-living and any ad hoc increases.

(3) The retirant shall be paid such adjusted annuity for each month thereafter.

(c) The Board of Trustees of the Arkansas State Highway Employees' Retirement System, by regulation, may reduce the amount of creditable service required to retire voluntarily regardless of age from thirty (30) years of creditable service to an amount of no less than twenty-eight (28) years of creditable service, if the board determines that the change is fair and just to the members of the system and that it is actuarially appropriate.