clicking on 'add traffic' as katmar suggested or anything in tomtom home software didn't do anything for me in my situation. i'm not sure if everyone has the same thing going on in preventing the traffic conditions from showing.
i've gone through the tomtom site a few weeks back and looked at the traffic sidebar and realtime traffic documentations. when you click on the sidebar, it's supposed to go into a settings menu. sometimes it doesn't work or you have to click the far right edge of the screen. but, if you dig around in the settings somewhere there's an alternative way to the same settings menu.
in there they have an option to change traffic frequencies. i've never touched those settings before or seen it prior... so i can't say whether the channel changed or what happened to alter traffic for me. i dug around on the web a bit and found info for my region by clear channel. navteq has a similar service i hear but clear channel had more choices in my area:
http://totaltraffic.com/CoverageAreas/
in my case, the frequency was already pre-set at 88.1 fm but i could not find any information regarding traffic data coming from such a frequency. so, i picked a different frequency in my area and didn't see any immediate difference.
i read somewhere that if it cannot find data in that frequency, the navigation is supposed to flip around until it finds a suitable frequency automatically. however, i don't know how reliable or fast that behind-the-scenes action is since it's supposed to be transparent to the user/driver, who cannot see the details or status of it. it could have been stuck at 88.1 receiving nothing.
this issue left my mind after that, but a few weeks later i noticed i'm receiving traffic data again. it's traffic data, but doesn't seem like it was before. any difference why that is could just be psychological or maybe actual, but since i wasn't paying attention at the time it originally worked, it's tough to say.
so, i would suggest to pick a frequency for your area and wait a bit to see if something happens. if it doesn't then change to another channel and go from there.
this realtime traffic seems so casually passive in implementation, not seeing all the nooks and crannies of traffic data retrieval.
On a related note, does anyone know how to turn Traffic OFF?
as a possible workaround, try switching to a non-working frequency. let us know if that works or if the nav system auto-changes until it finds a working one.
edited for clarification.
tomtom nb-1 has two versions: the live version and the non-live version.
with the live version, overseas owners are able to subscribe to traffic services, weather forecasts and other information in addition to an rds-tmc option -if the country or region supports such a service.
in the u.s. and perhaps canada, our nav systems are non-live versions(unfortunately) - so, no live subscription option. we only receive data via radio frequency. the underlying tech is rds-tmc, which i assume this discussion involves.