The Traffic Message Channel (TMC) is a digital data channel provided by the traffic news service that supplies continuously updated 'real time' traffic data. When your route has been selected, our navigation systems with dynamic route guidance make use of this data to check traffic conditions. If the TMC indicates a traffic jam or other hold-up, the system automatically calculates an alternative way to your destination. It takes into account the time required for the alternative route and if this is longer than driving through the traffic jam, your route is not changed. The Traffic Message Channel is now available in much of Europe with data transmitted digitally, decoded by your navigation system, and displayed in your own language.

Article source: www.volkswagen.co.uk