ribit:
re: "they can sample the speed and direction of travel of other cars with gps. Ya gps device is telling on ya every minute."
Here's a forum that has disagreeing explanations from two people. The first one says what you think, that they're sampling info from other GPSes and using the information they provide to determine road conditions. The second one says what I think, which is >NO< that's not what's happening: There are offices that compile traffic reports and broadcast the results. The GPS just picks up the data and lets you know when there's something that affects your route.
One reason I believe the latter explanation is that GPSes are too inexpensive to be both broadcasting and receiving. Another is that I've seen traffic warnings from my GPS and they are flat-out WRONG. The GPS tells me that there's a huge slowdown ahead but I make it home in excellent time. That wouldn't happen if they worked the way you suggest.
Mind you, I don't consider this issue to be decided. You might be right. Maybe we should ask zzfart. Whatever he thinks is bound to be wrong.
http://www.reddit.com/r/explainlikeimfive/comments/368gql/eli5how_does_my_gps_know_there_is_traffic_ahead/
Gold is $1,581/oz today. When it hits $2,000, it will be up 26.5%. Let's see how long that takes. - De 3/11/2013 - ANSWER: 7 Years, 5 Months
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