Channel Comparison: XM Radio vs. Sirius for Traffic Radio
Traffic on the radio can help you avoid unnecessary delays and congestion. Satellite radio provides continuous traffic in many major metropolitan markets. By having channels dedicated to traffic news, the satellite format can provide better information than on a broadcast channel with periodic traffic reports.
XM Radio has more channels, as Sirius doubles them up. You can see the lineup below. If you are driving in San Diego, you may not care about what is happening in Phoenix on the same channel, but with the constant traffic reporting available, you should still be able to get the information you are looking for.