(

a) This

section applies only to a county of the first class, as defined by

Section 28020, as amended by

Chapter of the Statutes of 1971, and

Section 28022, as amended by

Chapter of the Statutes of 1961. (

b) Notwithstanding Sections and 31461, neither “compensation” nor “compensation earnable” shall include any of the following: cafeteria or flexible benefit plan contributions, transportation allowances, car allowances, or security allowances, as enumerated in a resolution adopted pursuant to subdivision (c). (

c) Except as provided in subdivision (d), this

section shall not be operative until the board of supervisors, by resolution adopted by a majority vote, makes this

section operative with respect to any employee who becomes a member after the effective date of the resolution. (

d) Regardless of whether it has acted pursuant to subdivision (c), at any time the board of supervisors, by separate resolution adopted by a majority vote, may make this

section operative with respect to any member not represented by a certified employee organization who makes an irrevocable election to become subject to this section. (

e) Nothing in this

section shall be construed to affect any determination made by the board of retirement, pursuant to

Section 31461, prior to the effective date of this section. (

f) Nothing in this

section shall be construed to affect the validity of any memorandum of understanding or similar agreement that has been executed prior to the effective date of this section.