Abstract: A horizontal position and vertical elevation measurement apparatus and method for measuring horizontal positioning and absolute elevations of railways, paved or unpaved roadways, and other travel surfaces. The apparatus is capable of determining longitudinal and transverse elevational profiles in an X-Y-Z coordinate format usable with Geographical Information Systems (GIS) and Land Information Systems (LIS) to project present and future traffic counts and traffic flow patterns. It can measure the horizontal location and elevations of paved and unpaved travel surfaces, potholes, cracks, wheel ruts, etc. within a travel surface, and the horizontal location and elevations of railway tracks when conventional railroad high rail gear is used. The apparatus has Global Positioning System (GPS) signal receiving units fixed to each end of a sensor bar mounted on a vehicle perpendicular to vehicle movement.