In Belgium, at least one company does this with simple mobile phone signal, no additional software to download: http://www.be-mobile.be/
Example in a national newspaper: http://trafic.lesoir.be/?act=infotraf (only tick "Bouchon" if you only want to see traffic jams ; colours show mean speed of cars).
Of course, nobody never sign anything about using their phone signal to something else than making and receiving phone calls. Providers just did it without the consumer consent. And nobody said anything. That's Belgium...
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In Belgium, at least one company does this with simple mobile phone signal, no additional software to download: http://www.be-mobile.be/ Example in a national newspaper: http://trafic.lesoir.be/?act=infotraf (only tick "Bouchon" if you only want to see traffic jams ; colours show mean speed of cars). Of course, nobody never sign anything about using their phone signal to something else than making and receiving phone calls. Providers just did it without the consumer consent. And nobody said anything. That's Belgium ...