In general, the mile markers are measured from west to east and south to north. Such as I-10 starting in Escambia County, bordering Alabama, with mile marker 1 then increases eastward. And for I-95 from Miami-Dade County starting with mile marker 1 then increases northward. The data is refreshed weekly and changes are made by the District Offices who are responsible to collect and upkeep the data. This data may also be collected for call boxes that are located at integral milepoints instead of the usual mile marker signs. This data is required for all interstate, tolled or non-tolled expressway facilities, and US routes. This dataset is maintained by the Transportation Data & Analytics office (TDA). The source spatial data for this hosted feature layer was created on: 05/03/2025.For more details please review the FDOT RCI Handbook Download Data: Enter Guest as Username to download the source shapefile from here: https://ftp.fdot.gov/file/d/FTP/FDOT/co/planning/transtat/gis/shapefiles/milemarkers.zip