The Radio Data System (RDS), which is covered by the United States Radio Broadcast Data System (RBDS) Standard, was developed for Frequency Modulation (FM) by the European Broadcasting Union (EBU) and its member countries. It is a form of a data coding channel designed to operate in conjunction with commercial FM radio broadcasts. One of the most important features of the RDS is the Traffic Message Channel (TMC) which has the capability of superimposing inaudible data on existing FM station carriers. These data can then be selected for display or speech synthesis by in-vehicle decoders. RDS encoders are added to FM transmitters for the primary purposes of identifying radio broadcasts. These broadcasts can be subsequently decoded by receivers which, at the user option, can be self - tuning and capable of automatically selecting the strongest signal carrying a particular traffic program.