I just got a GPS nav system in the E - a Pioneer AVIC D2. Heading back home this weekend, I was about two hours out when I decided to take note of the estimated arrival time and see how close the system would guess. I was using cruise, trying to maximize my MPG, which I was also testing, so I kept a steady speed the whole trip as much as possible.

Two hours out it nailed it within one minute. By the 1 hour, 30 minute mark it had it nailed to the EXACT minute, when I would pull in to my driveway at home.

Kinda cool! :cool:

If you are just doing Interstate driving, it works great. Given the way most nav units work, they have different travel times for freeways, highways and local streets. While I can set the unit's computation speed for highways at anything I want on my Eclipse, it doesn't always work. I set if for 40 MPH, which is about right for highways in and around town. If I'm driving across the state, those same highways are 55-60 MPH. That totally goofs up the time calculations. I could reset the highway speed in the nav for those trips but I don't.

I know with my Kenwood nav it self corrects along the trip depending on my distance from the destination and the speed I'm traveling. It doesn't roll back and forth thru the minutes like a kid bouncing on a scale but it shaves off or tacks on time every few minutes depending on those variables. So I can't actually beat the clock or have the clock beat me because it's actually pacing me. If I'm at a stand still it will just make a calculation based on my distance and the average speed to travel that distance.

If I was cruising at 55 and then started a nice 10 mile stroll going 85 I could watch the ETA time start dropping down every couple miles or so.

Yeah, the AVIC does the same thing, constantly updating the ETA... in fact the arrival estimate varied by as much as 2-3 minutes along the way, but I was judging it from the point I made a mental note of the ETA, about two hours out from my destination.

I was wanting to see what the unit had programmed in as a cruising speed, but its one of those functions I can't access unless the parking brake is on, so I kept forgetting to check until just now. Turns out it is set at 70 mph - which was the exact speed I was traveling.

This morning it also nailed my 20 mile commute to within a minute. Mostly highway and again with the cruise set exactly to 70 mph whenever possible. So yeah, I'm optimizing for success (especially since my actual cruising speed was coincidentally EXACTLY what was programmed) but I'm still impressed. I definitely don't expect it to do very well once traffic and stoplights come seriously into play, even if I got the XM traffic feature installed.

:cool: