In 1955, Senate Bill 66 was passed, and the Highway Employees' and Highway Patrol Retirement System was established.  Senate Bill 66 became effective August 29, 1955. On October 1, 1955 the system accepted 109 retirements.

Legislation to grant retirement benefits to long-term employees was the result of work done by some industrious employees of the State Highway Commission, the State Highway Patrol, and the Highway Employees' Association. Those involved negotiated an arrangement with the State Highway Commission to forego a future employee raise in order to fund the first contributions of the retirement system.  In the initial negotiations, it was agreed that the new retirement system would be funded by contributions from the employees of the State Highway Commission and Missouri State Highway Patrol and by contributions from the two agencies.  The initial contribution rate for both employees and employers was 4%.

In the late 1970's, legislation was passed to make the retirement system non-contributory for members, with the only contributions being made by the Highway Commission and Highway Patrol. The system remains non-contributory for employees today.

The retirement system's Board of Trustees, identified in the initial legislation, consisted of the Missouri Highway Commission, the Chief Engineer of the Highway Department, and the Superintendent of the State Highway Patrol.  In 1955, the state highway commission consisted of four members with the state geologist being an ex-officio member of the board. Additional legislative changes were made in 1965, 1981, 1988, 1992, and 1999 -- culminating in the current board structure. 

Today, the eleven-member board is made up of three Missouri Highways and Transportation Commissioners, the director of the Missouri Department of Transportation (MoDOT), the superintendent of the Missouri State Highway Patrol (MSHP), a state representative, a state senator, an active MoDOT employee, an active MSHP employee, a retired member of MoDOT and a retired member of MSHP.

For the first 35 years of its existence, the retirement system was operated as a unit of  the State Highway Commission.  Highway staff was assigned on a part-time basis to carry out the system's business. 

In 1988, the first executive director position was established. As the membership base and the assets of the system grew, it became clear that full-time staff would be required to provide continuity and direction to improve and advance the system. Since that time, numerous staff positions have been added.  Today, the system employs 12 full-time staff.  Recent additions to the staff include the chief investment officer, general counsel, and senior financial officer.

Today, the system operates as an independent trust fund under the direction of the Board of Trustees.  In August 2002, a building was purchased to provide a permanent home for the retirement system.  This step was taken to ensure the system could provide a comfortable, accessible environment for members to meet with staff to discuss their benefits.

The system is now known as the MoDOT and Patrol Employees' Retirement System (MPERS) and provides retirement, survivor, and disability benefits to over 17,000 members.  The assets of the trust recently achieved $1.8 billion with investment returns for the fiscal year achieving 18.1%.