Arrival time

it adjusts the arrival time every so often, when you start it will give an arrival time but after breaking all land and sea records, it will adjust as you go, so by the time you get there it should be right on.

It's a simple speed/distance calculation, although it adds a set road speed in the beginning. Then, it recalcs to your speed after a while. No black magic, just math.

Garmin's Estimated Arrival Time algorithm does a really good job of it. I drove 280 miles today and the initial estimate was only 3 minutes off. And considering the route included interstate, federal, state and country roads, the estimate was right on--as usual.

I believe it must use some type of "running average" estimate of an individual's driving speed. That way it accounts for actual speeds as well as road conditions. Anyway, whatever it does, it works.

Question : Can I train my Garmin to provide better estimated times of arrival (ETA)?

Answer:
Your device can actually learn from your driving and adapt its internal database to provide better estimates of your arrival time. The device will learn from a driver’s habits and adjust the ETA accordingly. This is done by observing what speed a driver typically drives on each speed category of road and using that data to compute ETA.

was how does the GPS calculate an accurate ETA before he begins to drive (at a rate that's over the speed limit)?

It's fine that it continually recalcs the ETA, but his question was how can it know he's going to drive 12 mph over the limit before he even begins the trip?

Edit: I see that canuk answered this.

My theory for the car GPSr is pretty much what everyone else is saying. With my Garmin, it doesn't use my current speed to do it's calculation. It's taking the distance I have left to travel and dividing it by the speed limits for those roads. I does adjust if you hit traffic or speed up.

But with my old Magellan, it does use my speed in the calculations. It's a hand held used for hiking, caching, etc. My theory on that one is that it's taking the distance to my destination (as the crow flies) and dividing it by my velocity in the y direction (the vector towards the destination). If I travel away from the destination, it gives me a ---- for the ETA because there's no velocity towards the cache.

I agree the Garmin does a great job at calculating the ETA.

I have gone over 6000 miles on this cross country trip so far and the arrival time has worked well.

I depend on it for an accurate arrival time. Only when road construction or traffic is bad, which it cannot anticipate, does it get it wrong.

I find that my unit does recalculate well over the course of the drive and surprisingly does seem to get a close estimate at the start....not knowing how I am going to actually drive the distance.

It rocks what else can I say?

If it keeps adjusting as you get closer, it's never wrong.

garmin is pretty good all things considering. i remember that it worked really well on my recent trip to montauk. i wonder if you have the live traffic subsciption if it calculate the time with the traffic.

Why does everyone keep answering a question that wasn't asked?

The OP asked how the GPS can provide an accurate arrival time *before* he begins his journey... which will include significant time spent driving in excess of the speed limit.

since I did it, but there is a setting area inside the Garmin unit where you can set the "actual speeds" that you travel for different roads. For example on a major highway, I set mine at 5 miles per hour over the "legal [really the Garmin set speed] speed limit". I don't recall where it was on my Garmin 750 but it's in there to fine tune the arrival time. Hope this helped.

nuvi arrival time is actually pretty bad, it makes no allowances for red lights, let alone other issues like traffic, and assumes that you always drive at the speed limit. But it does know the time, and it knows the distance to the destination, and adjusts the estimate as you approach the destination. Clearly when the distance becomes zero or within feet of zero, the arrival time will match the actual time.

How can I use the Garmin to get my wife to leave at the departure time I want?

would be labeled "spousal abuse" from throwing the garmin at her. It gets expensive on several fronts, lawyers, doctors and not to mention replacing units.

My fuzzy mind seems to recall seeing something like this capability somewhere, but I thought it applied to newer devices only. Does anyone know which devices this "learning" capability exists on?

Joe

I would like to know too. And how it is done.

canuk, thanks. I knew it had to be keeping track of my other trips. Sneaky little bastard

are very, very accurate too!!

You might use TTS VE and plug in appropriate harrasing words and phrases such as:
95: instead of, "please drive to highlighted route," you might say instead, "If you'd leave on time we could get to our destination on time."

Of course, if she's tech savvy, this probably won't help.

I'm pretty sure my nuvi 360 doesn't learn from my driving habits. I've made multiple trips from the KC area to the Twin Cities---straight up IH35. I alway drive at 74mph, always stop at the south Iowa welcome station, at Story City for gas and a drive throgh McDonald's, then again at the MN welcome station. Very, very predictable.

Nonetheless, my nuvi gives me an initial arrival time based on the distance/speed limit calculation, then adjusts to a sooner arrival time as I drive slightly faster, then adjusts to a later arrival time after I stop. I've checked my device and don't find any place where I can modify that calculation.

They don't store information from one trip to the next... but they do, as has been noted, adjust the ETA on the fly - as designed... the calculation is based on the classes of roads on your route, speed limits, and a guesstimated average speed... as one drives a route, if they are faster than this average expected speed, it shaves time as you go... or if slower, it adds time, and adds time for duration of stops.

And Ken, you should try stopping in Clear Lake once...

Yes, as I said, my ETA is adjusted to account for speed-up, short-cut, delay, stops, etc. Obviously, when I'm a block away my ETA is right on. I may have mis-understood the poster above who, I thought, indicated that it stored driver info. The original poster said his ETA as set in his driveway was always accurate, even though he exceeded the speed limit by 12 mph. I don't know how that could be.

Clear Lake; been there, done that. But, I must confess that it was rainy when I was there, and I didn't get the full advantage of the Surf Ballroom (closed) or the crash site (rain). I'll put that on the agenda for another trip one of these days.