The Traffic Message Channel (TMC) is used to broadcast information about local traffic conditions using the FM Radio Data System (RDS). Some GPS navigation systems can use RDS-TMC traffic data to help avoid road segments with traffic problems.
In the United States, TMC traffic data is available in many larger cities from Clear Channel’s Total Traffic Network. Clear Channel TMC competes with XM NavTraffic.
In the UK, TMC service is available from Trafficmaster Plc.