[snareman]

I have my nav set to "frastest" route. In many cases it will route me in a way that I know is longer. You could argue that it doesn't know the shorter way, but if I start driving in that direction then it will appropriately route me that way. Just the other day it told me it was going to take me 20 min to get somewhere. I started driving the shorter way and after it corrected its route to that way the ETA was cut in half down to 10min. So obviously it knows the route exists and is faster, but doesn't take me that way

Why does it do this? Anyone else have this experience?

[poiney]

It does all sorts of crazy things, some of which can be explained by inadequate info for RTTI.

I find main problem is during rush hour traffic on freeway, when it doesn't assume any issue with side streets. However, it still has relatively-correct speed info for highway traffic that I can see by the black arrows. It will routinely re-route me in slow traffic to side streets, that has 4 times the distance. Seems that Navi would need to estimate that I need to go > 80mph (average) on side street to break even.

This nonsensical result tells me that the computer may assume that if slow traffic occurs it may think that it will worsen to dead stop, so that its algorithm recommends reroute. Period. That's my guess.

The re-routing info also seems to be highly sporadic and "indecisive", as if it is simply displaying the results of possible alternative routes before "concluding" the best path.

Most of the time it is good for indicating slow traffic from traffic accident, but some times, no response.

Lot of hit and miss with RTTI at the moment that is sure to improve next generation.

[snareman]

I'll go with you on all that except for that there is no RTTI in my city yet. So that shouldn't be causing it any confusion.

as an aside, I'm thinking that RTTI is still sort of in its infancy as a technology, but that a few years down the road will be much nicer.

[JNMACE]

It gets worse...not only will it take you the long way, down unnecessary side-streets, but I found that it often didn't notify me to make a turn until I had passed through the intersection! The Nav system is pretty frustrating...my Blackberry gives better navigation and directions truthfully...

[Bimmer335i07]

I noticed that if you used fastest route, it will sometimes be longer in distance, because it chooses highways, freeways etc... to get you there faster. If you choose the shortest route, then it will choose the shortest distance, but it will mostly use local roads where there are traffic lights, which might get you there in a longer period of time.

That's what I've noticed.

Hope this helps!

Btw, I love the Nav. I have no problems yet. (knock on wood)

[snareman]

again, I agree, but it calculated the first route at 20min and when I started heading in the direction I knew was shorter, it revised its thoughts and came up with the new route that was only 10min. Shouldn't it be able to make these comparisons "in its head" before it shows me the fastest route its picked?