Most nav units do have traffic information piped in over TMC (radio):
http://en.m.wikipedia.org/wiki/Traffic_message_channel or satellite radio.
But the maps software itself is often unable to draw incidents on the actual maps, which is a bummer. Google had to do some code-fu to make it work with their maps, and it works more easily because they get their information in a different format from web services rather than TMC.
In the case of the Camry, that's pretty cool that it had that support. Wish OEM manufacturers felt it was worth the time and effort to draw traffic colors on top of the roads.