Hang the possible privacy issues of your beaming your current location to the rest of the world. (Cell phones already pretty much have that one nailed.)

This device just is not necessary. There is another item that most cars already have installed in them that provides similar information in nearly real-time... It's called a "radio". There are these wonderful people on radio stations in major population centers all around the country who actually scout for traffic situations and advise drivers in advance, so they can route them selves around bad traffic areas. Pretty ingenious, and it's largely hands-free.

That hands-free option is another great little add-on. Because the next traffic report you hear from your GPS device could sound like this...

"Warning... Traffic ahead caused by six car pileup. Fellow driver attempting to play with GPS and not looking where the hell he is going... Shall I suggest an alternate route? Oh, wait... Now you have cause a six car pileup. Nice going, numb nuts..."

I love my GPS (hand-unit for hiking and travelling; not for driving) but do we really need one more piece of techno equipment taking the eyes of the billion idiot drivers of the world off the roads?