Lots of posts on this subject already.
The nav already calculates multiple routes, and you have the option of selecting which one before you start.
I don't remember the exact button, but it's in the top right when it shows you the overall route, before confirming to start.
You can cycle through the various routes, the first one shown isn't always the best one.
Updated firmware comes together with updated maps. If you're stilling running a 2005 disc, then that's half the problem!
The nav already calculates multiple routes, and you have the option of selecting which one before you start.
I don't remember the exact button, but it's in the top right when it shows you the overall route, before confirming to start.
You can cycle through the various routes, the first one shown isn't always the best one.
Updated firmware comes together with updated maps. If you're stilling running a 2005 disc, then that's half the problem!