Warning system for road users, used to warn of e.g. speed limits, involves sign sending encrypted signal to vehicle so that audio or visual warning signal can be generated inside vehicle

摘要

A transmitter (2) in the vehicle sends a signal (2a) to a road sign (4) to which a code (4a) corresponding to the information displayed on the sign is assigned. The sign then sends a response signal (3a) which includes a code (3a) corresponding to the information displayed on this sign to a receiver (3) in the vehicle. Circuits (5) connected to the receiver decrypt the code in order to generate an audio and/or visual signal corresponding to the displayed information.