Traffic Live employs crowd-sourced real-time speed data from over 1.3 million drivers including other Navigon app users, commercial fleets such as trucks and taxis, and regular drivers with a GPS system. The feature also utilizes an intelligent fusion of information from traffic cameras, road sensors and conventional traffic messages coming from ClearChannel’s Total Traffic Network.Navigon Traffic Live is offered as an In App Purchase for $24.99. The app can be purchased for an introductory price of $19.99, till next four weeks.
Are you using a 3GS or a 3G? On my 3G I find the UI of Navigon definitely slower than TomTom, but even TomTom runs like a pig compared to the AT&T Navigator app.
The traffic setting does give you the option of sending your location and speed data. This can be turned off but is on by default. This also may be what the spinning gear that I've noticed is doing.John
This quote would indicate they're using Inrix data, based on the reference to the number of probes: