There's some question as to whether the nuvi's "learn" your driving habits. For instance, I tend to drive a bit over the speed limit on major highways when trafffic allows. Usually 10 miles over when I can get away with it. On local roads, I follow the posted speed. As just a part of my research, I'd appreciate anyone interested in participating to enter two different routes and post the estimated travel time, as well as distance driven. If you don't mind noting your driving habits, as well as how long you've used your nuvi, the model, and which map version. I may find there's nothing to some of the recent posts, and a different test may also be necessary to help confirm any results I think we have. The two routes are:
400 W. Livingston St, Orlando, FL > 2 West Bay Street, Savannah, GA. (primarily Interstate driving)
235 Main St, Nashua, New Hampshire > 13 Lily Bay Road, Greenville, Maine (a mix of roads)
I really appreciate any help with this.
Last edited by gatorguy on Mon Jun 16, 2008 9:20 pm; edited 1 time in total
Route preferences (fastest, shortest) and avoidances might also need to be known. Also make certain no traffic receiver connected. (Does it cache info?)
Last edited by Tim on Wed Jun 18, 2008 1:38 am; edited 1 time in total
Joined: 04 Dec 2007 Posts: 303 Location: Central California
Mon Jun 16, 2008 9:36 pm
Gator,
What were your results?
I had mine on shortest and then realized you probably were using fastest route. I was up in San Jose and computed someones driving to save on gas. If they took the freeway, it was 14 miles and only 10 taking the back streets. Kind of a no brainer at today's gas price to take the back streets and only lose a minute in travel time.
Forgot to put back to fastest on the way home, experienced all kinds of weird directions taking me off the freeway. Sometimes right back on at the next on ramp.
My results (fastest) Route 1 - 280 miles and 4:06
Route 2 - (fastest) 260 miles and 4:30
Nuvi 760, 3.00 firmware, 2009 maps. It should be noted that I reset mine over the weekend and have been driving very very conservative all day (about 90 miles today). Doing this simply to check things from a different angle. All driving today was primarily local and some state roads, no interstate.
@Tim, no traffic considered on mine as I have it disconnected and on battery for this route check.
EDIT: The first route is one I actually drove two times last week, with only a change on the route start. I drove that one at or below speed limits on the return trip. I'm guessing that resets may not completely clear the stored "driving history" if it exist at all. Certainly not claiming it does.
75 for much of the way, dropping to as little as 50 (I think) around Jacksonville, and 70 in parts of Georgia. Driving at the speed limit, the trip should take about 4:15 or so. I don't know if the nuvi assumes any driving breaks or not. But I don't even want to worry about that yet.
My son reminded me that the time from downtown Orlando to Savannah was 3:42 on the 760. He was fascinated by the two gps's, so I'll go by his figure since he seems very sure. Even used his cellphone to run Telenav on the way back to compare to my PND's. Of course I was driving at or 5mph over on the way up.
@YourFun, not sure why there would be any difference.
5 mph over . . . I guess sometimes as much as 15 . And you know that people were passing me! I did drive much better on the way home. My gas mileage on the way up averaged 23.7, but on the way home 25.8. Definite advantages to driving 65, I found out.
Joined: 04 Dec 2007 Posts: 303 Location: Central California
Tue Jun 17, 2008 1:20 am
Sometimes when I'm in Routes, press Go!, it doesn't display arrival time or the turn times. Yet when I have it simulate route, it always shows the time in lower right and left corners.
I have also had the selected voice drop out once and another time after using FM, I had no voice until I went back into FM and out again.
Also when I used the FM transmitter, it would look for stations and then tell me where to tune. It did this at least 10 times. Now all it does is ask for a station number. It works great in the 99 Mercedes and hardly hear it in a 2007 Infinity.
Do I have an intermittent unit, should I return it or see what happens next?
Joined: 09 Jun 2008 Posts: 78 Location: Pittsburgh
Tue Jun 17, 2008 1:37 am
I bought my 750 primarily for use while doing service work. I serve equipment for two different companies and I cover half of Pennsylvania.
Today I went from Barkeyville Pa to Bellefonte Pa which is about a 2 hour drive. The Garmin estimated my TOA of 2:11 and I got there at 2:10. On the way home which is a 3 hour drive the Garmin was within about 2-5 minutes of being right on. I am quite pleased with the unit.
But the Go Home route had me routed to go on back country State routes. I had to drive by 2 of them while on Rt. 80 before it had me on the right road, Rt. 79. My 750 is set at Fastest Route.
I do like how fast it 're-calibrates' the route though, in a matter of seconds if you pass up your road. Very nice. My only beef is that the volume on the voice is way too low.
So that this thread doesn't end up as a general discussion of routing, could you also post your estimated travel time results for the two routes in the first post? I'd love to be able to determine if the nuvis are able to adjust their travel estimates and/or routing based on your personal driving habits. We'll need several responses to be able to see if a pattern emerges.
Joined: 04 Dec 2007 Posts: 303 Location: Central California
Wed Jun 18, 2008 1:35 am
My Nuvi 760 continues to deteriorate. Now when I don't want to navigate to start point, the unit tries to do it anyway. Enough is enough, it will be returned to Costco.
Last evening I ordered another 760, my friend will also be receiving one. I will put the same coordinates in each and see if they are the same.
Two people now have given their miles in tenths. Does anyone have any idea why the difference?
Pageda, I noticed you posted results from two different runs. While the shortest remained the same, the fastest changed. Did you do these simulations on two different days? Or perhaps I'm just misunderstanding what you meant by Run 1 and Run 2.
Joined: 18 Jan 2008 Posts: 35 Location: Ottawa, ON
Wed Jun 18, 2008 2:25 am
"Two people now have given their miles in tenths. Does anyone have any idea why the difference?"
Start the route and go to the speedometer page. The distance in the top right corner will be to one decimal place. I get 279.5 miles for Route 1. The distance shown in the routing area is rounded off. I get 280 miles there.
Joined: 04 Dec 2007 Posts: 303 Location: Central California
Wed Jun 18, 2008 5:06 am
I discovered in order to recalculate quickest time, it is necessary to recalculate on shortest time and then go back and push recalculate quickest time.
My new times have had 7 and 6 minutes added to them. Possibly due to my slow 1 1/2 hour driving time trip into town today.
Joined: 13 Feb 2008 Posts: 162 Location: Northern Va, US
Wed Jun 18, 2008 12:24 pm
Quote:
When I recalculate the 2 routes, the numbers still comes up the same. Why one would be different is beyond me.
I've have to believe that the differences in our locations and the positional differences in the satellites from one run to the next must have some subtle impact on the final outcome of the route information which still fits within some vendor defined acceptable deviation tolerance. If this was purely deterministic we'd all be getting the same result. The fact that some posts show the same unit deviates from one run to the the next must mean the route function is not an exact science and is influenced by differences in the environment from one run to the next.
That is why gatorguy proposed this test using an offset starting location for all of us. By using the 'set loc' function we are all starting from the same place and looking at the same routes without needing to worry about GPS drift as it applies to your current location and any routes you test the same theory on from your location.
Joined: 13 Feb 2008 Posts: 162 Location: Northern Va, US
Wed Jun 18, 2008 1:47 pm
Tim wrote:
That is why gatorguy proposed this test using an offset starting location for all of us. By using the 'set loc' function we are all starting from the same place and looking at the same routes without needing to worry about GPS drift as it applies to your current location and any routes you test the same theory on from your location.
understood...and it's just speculation on my part. But, even though we all use the same starting location, we are still all at different points on the globe and the satellites move from one run to the next. It feels like those uncontrollable factors are influencing the outcomes.
Joined: 04 Dec 2007 Posts: 303 Location: Central California
Wed Jun 18, 2008 2:04 pm
raaurora wrote:
Quote:
When I recalculate the 2 routes, the numbers still comes up the same. Why one would be different is beyond me.
I've have to believe that the differences in our locations and the positional differences in the satellites from one run to the next must have some subtle impact on the final outcome of the route information which still fits within some vendor defined acceptable deviation tolerance. If this was purely deterministic we'd all be getting the same result. The fact that some posts show the same unit deviates from one run to the the next must mean the route function is not an exact science and is influenced by differences in the environment from one run to the next.
jmo.
If you will look at my post dated Wed Jun 18, 2008 5:06 am You will see that I was in error thinking that I had recalculated. Both calculations are now coming up the same.
I'm seeing differences right here in my own back yard. I also see no reason to believe our position on the globe would have anything to do with the calculations we are looking at.
The only part of this test I'm still (slightly) worried about is the impact of traffic receivers. While we might have disconnected the traffic receiver, it is plausible that some traffic data could still be stored on the device and being applied in some manner. It is probably unlikely, and even if it is impacting the route there is pretty much nothing we can do about it-- but it is worthy of mention.
Joined: 04 Dec 2007 Posts: 303 Location: Central California
Wed Jun 18, 2008 2:24 pm
You may be right. Especially since some have come up with a different mileage along with a different time.
I was surprised yesterday when a barricade was put up on a small section of roadway. My GPS already knew about it and had been telling me to go what I thought was the wrong way.
I hope with another few members posting results that we can begin to take a look at the data so far and see if there is any trend. I will have to say that I'm a bit surprised at the range of times so far. Seems as tho if the routes were computed based simply on the embedded map data that the travel time estimates should be nearly identical, as the route distances are not varying.
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. And you know that people were passing me! I did drive much better on the way home. My gas mileage on the way up averaged 23.7, but on the way home 25.8. Definite advantages to driving 65, I found out.