Updating driving speeds in the GPS

It's not been disabled, it's never existed.

I’m not quite sure I follow your post, but I’ll try to help clarify things a little. Firstly, in both BaseCamp (V4.2.5 - still on XP) and in MapSource the speed settings are for planning purposes only. By that, I mean that the algorithm that determines the route does not appear to use these settings. After BaseCamp or MapSource has determined the route, it then applies the speed settings to provide useful info in planning your trip.

It is possible that devices only use the preset speed values for ETA, but to me it would make more sense to make use calculations based on real-time values once a route is active. I’ve never owned an “On the Road” unit, but on my ancient device it was quite obvious that changes in speed during travel were altering ETA. It is less obvious on my newer device, but I suspect this is because it does a better job of smoothing out speed fluctuations. This smoothing would be important in city driving with stop signs/lights to prevent ETA’s from bouncing around. I suspect that real-time speed is still used, at least to some extent. I can imagine several ways of doing this, but I have no idea how Garmin actually does the calculation on their devices.

So, is your issue with ETA’s on the device based on observations while actually driving or based on statically reviewing the route on the device (default speeds would always apply)?

Like I said, I have never owned an “On the Road” unit, but as far as I know, none of the “On the Trail” units have had a means to set speeds.

Adding to that I believe nuvis will learn speeds as you use them and so ETAs become more accurate. This certainly seemed the case with my 1490 and now my 2508. I've also seen others comment that this is so although I've seen nothing from Garmin to confirm this.

Here’s a simple experiment to see if your device uses real-time data to determine. Using the Driving activity, create a route around your block or up and down your street – say at least a half mile/.8km in distance. Download the route to your device. Activate the route with the same activity and walk it instead of driving. Observe the ETA and see if it changes. It may take a little while - as I noted in my previous post, some sort of smoothing/delay would be a good idea to account for stop signs/lights in city driving.

All nuvis that I've owned adjust the ETA constantly as you're driving. I don't believe that is the issue the OP is concerned about, more that the ETA of his device and Basecamp disagree substantially and that driving speeds set in Basecamp have no effect on the nuvi ETA. I believe this has always been the case, at least since I started using nuvis, and including when I used MapSource.

All nuvis that I've owned adjust the ETA constantly as you're driving.

So what do you have against a little exercise?

Yes, ETA will constantly update, but I'll illustrate you two ways of doing it and how it relates to the experiment. One way is to use remaining distance and preset speeds for road types. Another is to use real-time speed and remaining distance.

In our walking experiment, the former method will always show an ETA of upto or less than 1 1/2 minutes in the future during the walk (for ~half mile trip). The latter method will cause the ETA to shift 7-8 minutes or so into the future at some point.

Both methods will approach the the correct value as the destination approaches, but the latter method will likely be more accurate the further out you are from your destination.

GPS Racing: Over 7 Million Brits Try And Beat The Sat Nav

How long will a journey take from point A to point B? To get the answer, many of us will punch the destination into our GPS satellite navigation devices which give us an estimated time of arrival (ETA).

However, a new survey thinks that subconsciously trying to beat the displayed ETA could be putting millions of drivers at risk.

It's known as GPS racing. Described as such it sounds fun, but it's leading to millions of motorists driving more dangerously. The ICM survey found that an estimated 7.2 million drivers in the UK alone have raced to a destination to beat the ETA predicted by their sat nav device, and half of those have admitted to breaking the speed limit in an attempt to beat their GPS in the last year.

SUSSAMB? :D

Nuvi learns your speeds or at least it used to.

http://www.gpsreview.net/train-your-nuvi-eta/

:)

As I posted above that certainly happened on my 1490 ... It also appears to be happening on my 2508, but far more slowly.

I have driven this same route about 30-40 times since I have used this 2797lmt and the ETA is always too high by about 30 minutes out of the 65 minute drive so this GPS does NOT learn driving speeds.

I have owned 8 or 9 Garmin units and the ETA is never based on my driving speed but the internal set expected driving speed.
However, this does not apply to GPS units without maps and databases. How could it? My original eTrex, without maps, (my first unit) bases the ETA on how fast you were travelling at the time as it has no map information or database other than basic maps.

As far as the updating the expected speed database I believe that may have been the case for my last 3 or 4 Garmin GPSes as I never had to or tied to adjust the speeds. They always seemed to quite accurate without my intervention. This one predicts some really bad ETA times and doesn't appear to be learning or my standard trip ETA accuracy would improve. Anybody know of a setting to enable/disable this feature somewhere?

The point of this thread was not the ETA time being correct but how to change the expected travelling speeds in the Garmin 2797 GPS to make it correct. In my previous units this was definitely possible in several of them that I tried with MapSource. I could download the MapSource settings into the GPS and read them back later. It seemed to be a very hidden feature to find, just as BaseCamp is now, and I don't remember it being documented how to insert these figures into the actual GPS.

I wonder if Mapsource will still run under Win 7 x64? Perhaps some reading of the MapSource manual on CD may help since BaseCamp appears to be a complete clone with a few twist and updates.