Those of us who have taken kids on a number of trips will inevitably encounter that age-old question, "When will we get there." I've been intrigued by how well a state of the art Global Positioning System can predict when you will arrive at your destination. For reference, I've been an active user of consumer-level products for several years, and while I have owned several state-of-the-art, dedicated units, I've ended up using Google Maps with turn-by-turn directions on my Nexus One (which remains ahead of competing offerings on an Iphone).

I use such a GPS regularly to monitor predicted and actual travel times between my home and work. My GPS collects traffic information about enroute congestion, has up-to-date road speed limits for the routes available to me, and uses this information to recommend the best route for me to get to my destination with the shortest travel time.