XPost: rec.arts.sf.written, rec.arts.sf.science   
   From: rod.speed.aaa@gmail.com   
      
   Greg Goss  wrote   
   > Doc O'Leary  wrote   
      
   >> Probably.  Many mapping apps have traffic congestion overlays.   
   >> The sooner you can get them that information, the better.  The real   
   >> problem, like I said, is when you wait to give it to them until it is so   
   >> late that they feel inclined to do something stupid in reaction to it.   
      
   > My wife has a fairly recent GPS in her car.  Once, we had programmed   
   > the destination into the unit because we needed it for the final   
   > navigation -- we knew the way for the first fifteen miles.  But, with   
   > very little warning, it abruptly told us to take an exit three miles   
   > before the obvious one, and adjusted the time-to-destination   
   > accordingly.  As we turned onto the overpass, we saw traffic   
   > backing up from something further down the road.   
      
   That is just poor implementation.   
      
   > At other times, it's given us a "congestion   
   > ahead" warning without changing the routing.   
      
   > How is traffic information sent to GPS units?   
      
   http://en.wikipedia.org/wiki/Traffic_message_channel   
      
   > Is it sent via the same satellites?   
      
   Nope.   
      
   > Other satellites (ex XM)?   
      
   Nope.   
      
   > Via the cell networks?   
      
   Some of the smartphone mapping apps do it that way.   
      
   --- SoupGate-Win32 v1.05   
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