Currently, most electronic toll collection (ETC) systems around the world are implemented by DSRC (dedicated short range communication) technology. However, area wide integrated MLFF (multilane free flow) road charging system is now currently on its development to replace DSRC-based ETC systems. VPS (vehicle positioning system) based ETC system is a category of location based service which tolls vehilces by determining if they move into the charging zone. It is an evolutional technology for area wide integrated road charging solution, which achieves the goal of electronic payment or electronic toll collection by a totally different scheme comparing to traditional DSRC-based technology. In this paper, the design and implementation of VPS-based ETC system is detailedly discussed, and a debit transaction VPS system field test had been practiced in the freeway of Taiwan.