2003 GMC Sierra 1500 Pickup Owner's Manual - Page 258

TRAF (Traffic): TRAF will appear on the display if the tuned station broadcasts traffic announcements. To receive the traffic announcement from the tuned station, press this button. Brackets will be displayed around TRAF and when a traffic announcement comes on the tuned radio station you will hear it. If the current tuned station does not broadcast traffic announcements, press this button and the radio will seek to a station that does. When the radio finds a station that broadcasts traffic announcements, it will stop. Brackets will be displayed around TRAF and when a traffic announcement comes on the tuned radio station you will hear it. If no station is found, NO TRAFFIC will appear on the display. For DAB (Canada only, if your radio is equipped with DAB), when the TRAF button is pressed, DAB does not seek to a station that broadcasts traffic. DAB only checks the current frequency for traffic support. This function does not apply to XMTMSatellite Radio Service. Traffic Interrupt Feature: Your radio can interrupt the play of a CD, or XMTM,or DAB station. Press the TRAF button. The radio will seek to a station that broadcasts traffic announcements. When the radio finds a station that broadcasts traffic announcements, it will stop. Brackets around TRAF will appear on the display. When a traffic announcement comes on the station that was found, you will hear it. When the traffic announcement is over, the radio will resume play of the CD, or XMTM, or DAB station. If no station is found, NO TRAFFIC will appear on the display. 3-103