2597 Learning Routes?

I seem to remember reading somewhere in the promotional materials that the 2597 will learn the routes that I like to take? I know that during rush hour, the route it tells me to take is generally slower, not due to traffic (so the traffic receiver isn't helpful) but just because of the timing of the lights.

After driving this route for about 2 weeks, it still has not learned my preference. Was there something I needed to turn on for this?