TMC is originally designed to be broadcasted via FM radio, this goes back to the late '80s when there was no internet in the average household and no smartphones existed.

The TMC feed is practically a dynamic text file (xml) aggregated in a traffic centre from thousands of signals (loops embedded into the roads, cameras, accident reports etc) and the TMC events are continuously being coded to the FM broadcast

To make life easier this XML file with the current traffic events is available online too so your smart device (tablet/phone etc) with no FM antenna can also have access to the same information what's being broadcasted via FM stations. On the other hand it obviously requires GSM reception and internet access.

Not strictly connected to the topic but but was brought up by someone here earlier that in most countries there are more than one TMC networks and one network usually broadcasts on several radio stations to provide decent coverage. The traffic horizon is usually 150-200km but this is usually the limit of the gps device to take into account when planning route. The other thing is the sort of traffic information being broadcasted by the given TMC network, it can be international, national, regional, local (int/nat/reg/loc) with most TMC networks not broadcasting cross border/international traffic data.

Sent from my Note7 FE - Flames Extinguished edition