How often is map (2009) inaccurate?

Isolated errors like that are fairly common but your experience sounds like something else. You may have a defective unit.

The factory supplied POIs sometimes have an address that is the owner's HOME.

determined which could account for the error:
http://www.poi-factory.com/node/16359

I also have found that my gps has recommended routes that are much longer than necessary, but I would have ended at the correct location. One other thought, if you know in general where you are going, look at the map view prior to selecting go...

to the reason your unit tried to take you 1.5 miles around.

Also, if you are not on a road (i.e in a mall or grocery store parking lot), and close to another road (behind the store?), mine has tried to take me to that other road and then around to my destination.

I've also noticed occasionally that traffic is being incorrectly reported on one tunnel in my area. In the mornings, the traffic is often VERY HEAVY going from the Portsmouth side to the Norfolk side of the Midtown Tunnel. In the afternoons, the traffic delays are in the opposite direction (most times). My 660 and 680 both report traffic alerts at that location on my route even though I am going opposite the delay. That is due (I believe) to the fact that the traffic is reported WITHOUT a direction in the traffic reporting system.

Regardless, routing with the GPS is often good and accurate, but like you reported, it can sometimes be off. I myself would rather get to an unfamiliar destination after a few minutes of extra driving rather than after a 1/2 hour of making wrong turns and asking someone for directions.

Joe

I downloaded the 2009 maps for my Nuvi 350.

While near Bufallo NY I wanted to have a coffee and ask for Dunkin Donuts location.

The GPS sent me at a dead end street in the middle of nowhere. I turn it off and set it for home which found it way out and look for a McDonald off the main HW.

Cheers

That's a very interesting link...thanks!

Prior to yesterday, I was under the impression that the GPS is never or rarely wrong, except if there are new developments that didn't exist when the map was created...

John

Heh......... they are often wrong. I used to use City Select v7 and then moved to City Navigator 2008. BOTH always told me to get on and off the freeway at 5th avenue in my town. There has NEVER been an entrance/exit there. The 2009 maps now know the correct street for the entrance but they don't understand the traffic flow so they tell me to go the "simple" way but it would be a drag to go that way. I'll take the "intelligent" way and make use of the light that lets me turn onto the freeway easily.

In the 3 months I've been using the 2009 map, I've had a couple of wrong turns. But this was due to the map being out-of-date (huh, imagine that...2009 is out-of-date and it's only 2008). There were recent developments in the town I was travelling in and it confused the hell out of my 760.

As long as it has good satellite reception, I think it is fair to say that a properly working unit is never wrong about where you ARE. Machines don't (usually) make mistakes.

Human beings who create the map and POI databases, however, often make mistakes or do dumb things. It is NOT the GPS that makes the mistakes but the dumb humans feeding it bad data !!!

I've lived here for just over 6 years and all maps still do not have this section of road (including google maps and microsoft's live maps). I've used the Garmin 350, 650, 660, 2720, and LG 730(?) with all maps from 2005 to 2009. Satellite shots are all correct, though. Hmmm . . .

Have you reported your missing street to Navteq? They are the company responsible for the maps. Their website is http://www.navteq.com/ , click on Map Reporter at the top to report map errors.

With regard to your comment about the satellite shots, please keep in mind that satellite shots are just photos taken from space and overlayed on the map data. So the satellite photo will of course show your road. While the map data may not until it has been corrected.