The Radio Data System (RDS) consists of a silent data channel already being broadcast by most VHF-FM radio stations in the United Kingdom. One of the additional features currently being developed for RDS is the Traffic Message Channel (TMC). This will provide motorists with a constant stream of traffic information, either displayed on an in-vehicle receiver or by speech synthesis. Significant work has already been carried out on messages to be broadcast, location codes and message management issues for RDS-TMC, which is reported in this paper. Through the European DRIVE Road Transport Informatics project called RDS-ALERT (Advice and Problem Location for European Road Traffic), this work is now continuing toward standards for RDS-TMC throughout Europe.