Mo. Rev. Stat. § 104.160
The board of trustees shall consist of three members of the state highways and transportation commission elected by the members of the commission. The superintendent of the highway patrol and the director of the department of transportation shall serve as members by virtue of their respective offices, and their successors shall succeed them as members of the board of trustees. In addition, one member of the senate appointed by the president pro tem of the senate and one member of the house of representatives, appointed by the speaker of the house shall serve as members of the board of trustees. In addition to the appointed legislators, two active employee members of the system shall be elected by a plurality vote of the active employee members of the system, herein designated for four-year terms to commence July 1, 1982, and every four years thereafter. One elected member shall be elected from the active employees of the department of transportation and one elected member shall be elected from the active employees of the civilian or uniformed highway patrol. In addition to the two active employee members, one retired member of the system shall be elected to serve on the board by a plurality vote of the retired members of the system. The retired member shall be elected by the retired employees of the transportation department and the retired members of the civilian or uniformed highway patrol. The first retired member elected to the board shall serve for a term which shall commence on January 1, 1993, and expire on June 30, 1994. Subsequently elected retired members shall serve for four-year terms commencing on July 1, 1994, and every four years thereafter, which shall coincide with the terms of the active employee members of the board. The board shall determine the procedures for nomination and election of the elective board members. Nominations may be entered by any member of the system, provided members of the system have a reasonable opportunity to vote.
(L. 1955 p. 718 § 8, A.L. 1981 H.B. 835, et al., A.L. 1988 H.B. 1643 & 1399, A.L. 1992 S.B. 499, et al., A.L. 1999 S.B. 268)