A statewide point dataset of Texas Reference Marker locations maintained by the Transportation Planning and Programming Division of TxDOT.  Reference Markers are extracted from the Geospatial Roadway Inventory Database (GRID), where they are maintained as an asset.  Reference Markers are located along all on-system (i.e. state maintained) Texas roadways at 2-mile intervals, with the exception of interstate highways, which have markers at 1-mile intervals. Reference markers are used as a linear referencing system for project planning, asset management, and as a location reference in the field.