Electronic toll collection system for toll road

摘要

An ETC system for a toll road includes a road-side device. The road-side device transmitting a polling signal. The road-side device receives a response of an on-vehicle device to the transmitted polling signal. A decision is made as to whether or not the response is received a plural number of times. In cases where it is decided that the response is received a plural number of times, next radio communications with the on-vehicle device are started.