The Radio Data System (RDS) enables users in the U.K. to pre-select the operation of a frequency modulation (FM) broadcast receiver. Similar systems are used in other European countries and in the United States. An FM broadcast receiver equipped with RDS capability is sometimes called a "smart radio."
The RDS enables a radio listener to scan for a particular type of program -- for example, current affairs, science, or popular music -- without having to constantly manipulate the tuning dial. A listener who is traveling or commuting in a vehicle can arrange to have special traffic bulletins break into programs automatically, even if the traffic information is broadcast by a station other than the one the listener is tuned to at the moment. In fringe areas, where reception of a particular station is marginal, RDS allows the receiver to automatically tune to a stronger station if there is any such station running the same program at the same time. An RDS receiver can also be set to display brief text messages from broadcasters, and to periodically re-set the car clock to show the exact time.
Besides the user convenience, RDS can enhance driving safety, because it lets the driver pay attention to the road instead of to the radio controls.