TomTom question

[charles p]

Wife recently bought a Tom Tom for us to use when driving rental cars on trips.  Her Lexus SUV has a GPS but the TT is much better.  How does the voice inside know you need to shift lanes and give so much detail about a route?  It's one thing to show a map, but this little device gives the user so much more travel info.  Is it possible that all the data is stored inside the device or does it download regional info from a satelite - or what?

I'm still in the dark ages I guess.

[oldandslow]

I don't know where it gets it's info but I can tell you that it can be wrong. Mine tells me I can make a left turn out of my driveway and drive 1 1/4 miles southwest to a highway into town. I have lived at this location for 48 years and that road to the southwest has never existed. I have also had it plot a route that would have taken me several miles farther on two lane roads rather than the normal route I drive on 4 lane roads. This summer in Colorado it showed me driving for 60 miles on no road at all and once had me driving in a lake. It did come in handy working my way around Santa Fe, NM but got me lost once I got around on the north side and I had to refer to a map to find where I was and get on the right road.

[Siskiyou]

Think of a GPS as a mini computer programmed to take advantage of maps and data loaded on the unit.  Interlinked with that is impute from Satellite signs which include position, date, and time. 

The satellite data works with the stored mapping data to provide information to the driver.  As your gps ages the on board data (maps, POI points of Interest, roads, and streets) becomes stale.  Just after I purchased my Garmin Street Pilot the State Highway Department made some major changes at an intersection, block of one exit and moving the operation about a mile and installing a street light.  When I head for the home of a fishing partner serviced by that intersection the gps still wants to send me down the old cut off route which has been blocked.

"How does the voice inside know you need to shift lanes and give so much detail about a route? "

When you impute a destination/waypoint your TomTom is looking ahead and when you are within a pre-programmed distance from the turn the unit has already calculated your route and it advises you of the lane change.  It is important that the driver keep his brain in gear.  The pre-programmed lane might be blocked because of contruction, accident or slow down and blindly fallowing the gps direction could lead to an accident.    The gps is a tool that assists the driver.  Interesting enough my new automotive gps displays the speed limit.  The other morning when I accelerated out on to the highway  the unit displayed the speed limit as 55MPH.  I was sure it was wrong when I observe a 65MPH sign ahead.  Just as I crossed the path of the sign the gps displayed 65MPH speed limit.  When I exceeded 65MPH the speed on the screen showed in red.

GPS units have flaws that are the results of programming error by map manufacture or the unit manufacture.  If it is an operating flaw many times the manufacture will provide an update to correct the problem. 
http://us.support.tomtom.com/app/home/?Lid=4&locale=en_US

At Christmas we gave the father-in-law a new automotive gps and helped him become and I found some new features that I like.  Interesting enough one of these features was on my Son’s old Tom Tom. 

About a week ago we bought me a new automotive gps unit that comes with one map update available during a limited period of time.  I downloaded it.