California Code, Public Utilities Code - PUC § 130110

(a) For employees of the Los Angeles County Metropolitan Transportation Authority not in a bargaining unit represented by a labor organization, the authority shall establish retirement benefits pursuant to Article 1 (commencing with Section 30400) and Article 2 (commencing with Section 30430) of Chapter 4 of Part 3 of Division 10.

(b) Retirement benefits for employees of the authority and any organizational unit of the authority in a bargaining unit represented by a labor organization shall be established pursuant to Article 3 (commencing with Section 30450) of Chapter 4 of Part 3 of Division 10.

(c) Retirement benefits for employees of the authority and any organizational unit of the authority in a bargaining unit represented by a labor organization that was created on or after January 1, 1999, for the purpose of representing managerial employees or supervisorial employees, shall be established pursuant to a collective bargaining agreement between the authority or any organizational unit of the authority and that labor organization.