Among elements of an intelligent transportation system for autonomous vehicles are embedded sensors for vehicle-to-structure and vehicle-to-road communications. Continuous operation of these sensors requires local electric power supply, especially in remote areas. Electric power sources are also needed for the structural health monitoring system, that is, for detecting any structural damage, whether natural (i.e. earthquake) or manmade (i.e. accident). Here we are providing results of part I of our unsteady numerical investigations for a generic vehicle (Ahmed body) passing under a freeway overpass at different distances from the side bridge columns. The study aimed at understanding the wind load on the bridge columns and wind energy potential generated from the passing vehicles at different distances from these columns under a typical freeway overpass that could be used for generating electric power. Results have shown that when the vehicle is at 0.75W distance from the bridge columns, an unsteady wind speed of up to 24 m/s is generated at the columns with a pressure coefficient of 0.9. Here W is the width of the vehicle. These results indicate with an appropriate system for harnessing these wind energy potentials, significant renewable electric power could be generated with zero carbon footprint.