My Traffic data was working fine, then suddenly it wasn't. A minor gotcha here: if you go screwing around in the settings, you can turn off the radio reception for the Traffic data. Unfortunately, due to bad UI design, when you then select the "show traffic data" from Navigation, it says something to the effect of "No reception". This led me to believe that either the data was no longer being broadcast (for whatever reason), or my unit was broken. Ideally, it should have said something like "Feature disabled" to clue me in that I'm an idiot and "broke" it myself
As I recall, the menu to reenable Traffic reception was on the second page of the Settings screen, so it didn't exactly jump out at me either when I was searching around for something I might have screwed up.