maps are better, yes but only the coverage
The last update of the maps has definitely improved the coverage of the area I live. Got to admit that. I have however still major issues with how the system routes me to a destination, and the estimated time of arrival.
I have tried to do the selecting of how to route me every time. I have not found that of any difference. Also, the new maps have not helped for the routing or ETA issue. The longer I look at this problem, the more I have to conclude that the problem is related to the TeleAtlas maps.
Recently I hooked my TT to my computer and looked at a route I drive daily. Almost 15 miles, about 1.5 miles surface roads (mostly 45 mph) and the rest freeway (65 mph). Under normal circumstances that takes me about 16 minutes (I do not travel during the rush hour). TT tells me it will take almost 25 minutes. When hooked up to my computer, I had this route run in demo mode. On the right bottom, it shows what speed TT thinks you should be going. I am not 100% sure (only 99%) that TT uses this speed to calculate ETA and also uses this to calculate fastest routes. And much to my surprise, the speeds are not even close to reality. TT wants me to go in demo mode just over 30 miles on the freeways, except one 1 mile stretch where I went all the way to 62 mph. But of a 13 mile freeway ride, doing 12 of those at just over 30 mph, I can see that the calculated time is wrong when comparing to reality. Really funny is that once I hit the offramp, I sped up from 30 to 50 mph while on the offramp. How poor the suggested speed is was shown in a stretch of road going through a housing development. Max speed there is 25 mph, but that is pushing the safety of you and the people that live there (yes, some people go through faster). TT wanted me to go 50 mph on that stretch. Scary.
Now, I am assuming that this average speed classification of roads is done by TeleAtlas. The GPS unit uses this information for it's calculations for the routing (in case of fastest route) and the ETA. In my example, 12 miles at just over 30 mph, 1 mile at about 60 mph and 1.5 mile at about 50 mph adds up to the about 25 minutes TT says it will take, so I am pretty sure I have figured this out the right way.
The calculations for the fastest route and ETA are 100% depending on the correct average speed data for all the roads. And I can demonstrate that this information is absolutely flawed (G rated audience statement). I usually phrase this differently, but could not post it here. And I thought that this was maybe for the roads that were new with the newest map data, but that is not true. Roads that are many years old also are rated wrong, at least in my area. Not all roads, but a lot of them. So, I think TeleAtlas has a lot of work to do. For some GPS users, ETA and correct routing is a must! If it is important for you, I am (at this time) not sure TT is the correct choice for you. If TeleAtlas fixes this problem, I think there is no nicer GPS around.
If you experience really bad ETA calculations, or really bad routing, you might want to verify the achieved demo speeds. If these average speeds are wrong, well, now you know why your ETA and/or route is wrong.