The German carmaker announced that its 2007 5 Series cars will have optional HD Radio. BMW has previously made HD Radio available in its 7 Series and 6 Series cars. The HD Radio format seems to be catching on, with 800 U.S. stations currently broadcasting it. The format lets stations broadcast multiple streams on a frequency with CD-quality audio on FM stations. The format also transmits data, so radio stations can send artist and song information, similar to the currently used Radio Data Signal format. CNET senior editor John Falcone talks about the format and reviews three homebound HD sets here: "Tune into HD Radio."