The Metro South corridor extends from the I-44 terminal station of the Cross-County MetroLink line to I-55 in south St. Louis County.  Metro South was originally the southern portion of the Cross-County corridor for light rail until segmented in the late 1990s. For earlier planning of Metro South as part of Cross County, view the shared planning history of Cross County.  Since the Cross County MTIA of Cross-County, Metro South has progressed in planning to an Alternatives Analysis and Draft Environmental Impact Statement (AA/DEIS), commonly known as the Metro South Study.

In the 1994 –1997 Cross County MTIA of Cross-County, EWG identified transportation problems and potential solutions in the north-south and east-west areas surrounding mid St. Louis County were known as the Cross-County Corridor. Out of that came a number of pidentified possible improvements including an extension of light rail into south St. Louis County.  At that time, a conceptual alignment using an existing Burlington Northern Santa Fe railroad right-of-way was identified within south St. Louis County.

Recently, East-West Gateway and its partners, Metro and Missouri Department of Transportation,managed the Metro South AA/DEIS to analyze alternatives extensions for expanding MetroLink into south St. Louis County. The purpose of the Metro South Study was to determine where a fixed transit alignment, along with station locations and park and ride facilities, should travel in south St. Louis County. The light rail alignment suggested during the Cross County analysis was reviewed again along with several other potential alignments developed during the study. At the outset, the only definite was where a Metro South extension would begin – Shrewsbury-Lansdowne I-44 station, where the Cross County MetroLink alignment opening in 2006 ends.

A key element of this study was that the study team, led by HNTB, coordinated transit planning with land use and transit-oriented development. This meant the team studied ways for light-rail transit to stimulate and/or continue economic development. As in other studies, In addition, the study team also considered social and environmental impacts, ridership numbers, the cost to build, operate and maintain an extension, and public input.

In late 2004, aAfter reviewing evaluation results and public input on potential MetroLink alternatives for the Metro South study area, the East-West Gateway Board of Directors adopted its staff's recommendation and deferred the selection of a locally preferred alternative (LPA). The three longer build alternatives of Orange-Reavis, Orange-Butler Hill and Blue-Butler Hill meet the study's goals and are competitive, but perform quite differently.  For an overview of the evaluation of the alternatives, view this table.

Changing conditions in the near-term plus other external factors could affect the costs and benefits of the alternatives prior to the project advancing into preliminary engineering.  Additionally, since the region does not have any identified local funding and there will be no application for federal funding at this time, there is no urgency to make a conclusive decision on the LPA.  To date, then, the Metro South Study  is completed but without any LPA recommended.