traffic sensing?

After I raved about my GPS' traffic sensing here, I have to admit that I've had a serious problem recently - the traffic sensing on my GPS has been useless for most of the last month.

I've been driving in multiple regions and for extended periods, and have been unable to get any traffic signals, except for the odd time when there's no traffic on the road at all. Weekends, rush hour, off-peak, major metropolitan areas, rural areas, everywhere. What the hell use is traffic sensing only when there's no traffic?! And why am I paying $9 per month for a non-functional service?

I did a search for "GPS traffic sensing problems" and found that my GPS (TomTom) is actually one of the better options on the market. I guess I just need to be a little more patient.