Does NUVI know better?

 

Last night I hopped in the car to pick up some take out from one of our favorite restaurants (about 10 miles). I have been driving this route for 20+ years.
Just for kicks I put the restaurant in NUVI and asked to take me there the fastest way.
Normally I take a main road, 4 side streets and there we are. Same return trip.
NUVI took me down the same main road, a little further to the Interstate, on the Interstate, off the first exit, a short way and we were at the restaurant quicker!
Except for major traffic times I will use the NUVI route in the future.
Many times NUVI does know better.
Try it sometime, it is interesting.

Not always

There are a great many times, and probably more than fewer, the routing in the NUVI is not the most optimal. My 885 consistently takes a shorter route based on mileage rather than the faster route base on road type and speed. There are just too many reports on this site about "crazy" routing where the unit wants you to take back roads, get off the Interstate only to get back on, routing you through residential areas with low speed limits, stop signs, lights and all kinds of traffic control and "calming" devices only because that route may be just a few feet (meters) shorter than staying on the higher speed highway or arterial.

--
Illiterate? Write for free help.

But A Lot of Times

I agree with both of you. A fair amount of times, my Nuvi wants to take me on what I think I know to be a not so good path. Once in a while though, I dutifully follow her instructions and am surprised to arrive sooner.

Traffic is probably one of the wild cards in my own experience.

Nuvi Learns

There is one route that Nuvi does for me that through both the 760 and 765T it wanted to take me on the four lane highway. Just recently it routed me the "back way" that I was doing all the time. There were no map changes between the choice of routes it was doing.

I think it is learning my preferences and accommodating them.

Street name seems more important than postal code

Yesterday I programmed a postal code on my Garmin. I did not pay too much attention to the street name as I could not find the name but the postal code seemed to send me in the correct direction on the map. I ended up 15 min away from the correct address. I reprogrammed the Garmin to find the street name by search all. I will be more careful in the future to make sure the street name pops up in selecting an address.

Very

nice!

--
Not doing anything worth a darn.

Varying Routes

LaManchaDQ wrote:

I think it is learning my preferences and accommodating them.

I wonder if Garmin officially documents this somewhere. I too suspect there is some kind of historical data involved, but Garmin would have used that as a selling point - but they don't. Just to see what route my Nuvi (350 1490t) wants to take going home and to work, I tell it to route to my destination. Sometimes I go off-route to do a stop, but I don't stop the Nuvi and just have it re-calculate. The weird thing is that the end of the route sometimes varies a bit, and I'm not sure what influences the decision one way or another. Weird. You'd think it would be deterministic. These are local roads with no traffic information.

routes

Sometimes mine will want to get off the interstate then get right back on? I have to take things as they come I guess

--
John_nuvi_

Off The Highway Then Right Back On

agg9900 wrote:

Sometimes mine will want to get off the interstate then get right back on? I have to take things as they come I guess

I had this happen to me on I-75 north of Lexington a couple of weeks after I got my first unit. Unit was set for fastest time, not shortest distance. I guess doing this was both shortest and fastest. I just laughed. Has not happened since.

--
mbrun

It's all in the Map that's installed

Almost everytime I update to a new map, my 660 does something different with routing to or from work. I use my 660 every day to and from work for traffic alerts. It has saved me many hours of sitting on the Interstate.

When I first got my Nuvi, it would tell me to turn left from the driveway to leave for work. That's quicker, but not shorter and also a dangerous entry on to the main road. So, I don't go that way (and neither do my neighbors).

A couple of map updates later, my Nuvi started telling me to turn right from the driveway, which was the way I wanted to go.

The last update it switched back to left. It also started to tell me to go around my block on the way home, which is more than 0.5 miles longer.

We'll just have to see what happens on the next update.

One thing that puzzles me though, is that if I plug in Sam's Club (from work) it routes me through city streets to get there and it's set for "Quickest" routing. Sam's is just off the Interstate on my way home and using the city streets takes 15 minutes longer. It would be quicker because it's shorter and more direct, but there are lots of traffic lights and congestion.

--
Metricman DriveSmart 76 Williamsburg, VA

Adaptive learning

akapauan wrote:
LaManchaDQ wrote:

I think it is learning my preferences and accommodating them.

I wonder if Garmin officially documents this somewhere. I too suspect there is some kind of historical data involved...

To a degree, this is true, I've never seen it documented, but it's provable. I know it applies to the nüvi 750, unsure about other models.

The algorithm used to calculate a route is the same whether in real time or in simulation mode assuming a traffic receiver is not in use and the ETA will be identical for either route. The ETA calculation is based on assigned speeds to road types.

I have the nüvi generate a route from my house to a point about 21 miles away that includes 13 miles of Interstate with a posted limit of 70mph. I then repeat in simulator mode and the duration to the ETA is identical. Here's where the adaptive learning comes in.

When using the nüvi, I normally tow a heavy trailer and rarely exceed 60mph on the Interstate. When the simulation has put me onto the Interstate, I switch to the odometer screen and the speedometer displays 58mph.

I thought this data might be coming from the track log, so I deleted it and repeated the experiment. It still showed 58 when I was on the Interstate. I then did a hard reset. It then displayed 70mph on that segment of the route and shorted the duration to the ETA. After a 300 mile trip that included some Interstate miles, a repeat of the same simulated route used before showed 61mph.

My conclusion is that the table of speeds stored in the nüvi to calculate an ETA becomes modified over time by the real time data it collects. For example, if you were to commute from home to work and back on the Interstate every day, and there was always a backup on that road such that you averaged 45mph over the course of some time, the nüvi would adapt to that speed for that type of road. When you later let it calculate a trip based on speed, it may take you off the Interstate favoring a different road type that would presumably get you there sooner. If this were true, then a hard reset would produce a route that favored the Interstate.

One caveat: Before doing a hard reset, be sure to have your Favorites backed up and some other settings such as keyboard type will go back to factory default.

--
"There's no substitute for local knowledge" nüvi 750, nüvi 3597

From Garmins website

TXRVer wrote:

To a degree, this is true, I've never seen it documented, but it's provable. I know it applies to the nüvi 750, unsure about other models.

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.

--
Nüvi 255WT with nüMaps Lifetime North America born on 602117815 / Nüvi 3597LMTHD born on 805972514 / I love Friday’s except when I’m on holidays ~ canuk

Nuvi routing

Unfortunately my Nuvi 1300 can not learn the route. Since I mainly use it for trips and not local, I will rely on my own knowledge around town.

In a few cases, I had

In a few cases, I had noticed that my WT learns my driving habits.

--
Garmin Nuvi 2555 LMT, Street Pilot C340, nuvi 265WT, Mio Moov 300, nuvi 255W, Navigon 2100 (Retired)

Not always.

Just yesterday, I had my nuvi send me south of a bottleneck (I was going waaayyy north of there) when I hit detour, on my way back from shopping. It did route me correctly going to the store when I hit detour, but not on the way back.

My destination was 3 miles north and it wanted me to go using a route I knew was ending in this intersection with the bottleneck (construction), so I hit detour again. It did use the same highway it gave me coming down there, so I thought it was OK, but NO. It took me south of the problem area and right into it with no way to get out, but going through it. This is why I'd love to see the "areas to avoid" feature available in all models, like the 8xx series. I was already aware of this construction area, and blocking this intersection would be something I would like to be able to do.

--
Garmin nuvi 1300LM with 4GB SD card Garmin nuvi 200W with 4GB SD card Garmin nuvi 260W with 4GB SD card r.i.p.

Quote: Sometimes mine will

Quote:

Sometimes mine will want to get off the interstate then get right back on?

Well, in my area, this is the trick to save 15 minutes during peak hours. While the lanes are all packed with cars, the exit ramps are mostly empty.

.

Albert2008 wrote:

Yesterday I programmed a postal code on my Garmin. I did not pay too much attention to the street name as I could not find the name but the postal code seemed to send me in the correct direction on the map. I ended up 15 min away from the correct address. I reprogrammed the Garmin to find the street name by search all. I will be more careful in the future to make sure the street name pops up in selecting an address.

A postal code does not specify an address, but rather an area - presumably the navigator took you to the center of the code in question.

And why wouldn't it?

canuk wrote:
TXRVer wrote:

To a degree, this is true, I've never seen it documented, but it's provable. I know it applies to the nüvi 750, unsure about other models.

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.

The only database that current Nuvis have is a table of the speed values for different road types. Note that this is NOT the speed limit database.

You can see what types of data the table contains by checking Mapsource (edit/preferences/routing/driving speeds), though the table in Mapsource is independent and the table in the navigator cannot be read or written to.

It keeps track of your overall average speeeds over the various types of roads and will adjust the arrival times based on that; Plus, if your unit has a traffic receiver, it can factor times based on delay values on the road segments (though this type of data should not, it does figure into the averages.

The only real problem with this is that if you have multiple drivers in your car the unit will take the average for ALL of the drivers, so if your wife drives 30 mph on a divided highway and you like to go 90, the reality is that you won't benefit from this adaptability.

At some point, it may well be that a detour will make more sense to the navigator than the one that seems obvious to the driver - if you usually travel at 85 on a highway rated for 55 - by way of example it may make more sense to the navigator to go beyond the usual exit and then double back over the returning streets if you aren't going to be limited to a 25 mph school zone.

And, if you calculate for shorter distances - or the highway has a delay, taking an exit and re-entering the road ausing the corresponding entrance could be determined to be 'faster' than just running at 10 mph on the crowded rtoadway. It is also 'shorter', if the exit, 'cuts the curve'.

It isn't complicated if you think about it.

--
Currently have: SP3, GPSMAP 276c, Nuvi 760T, Nuvi 3790LMT, Zumo 660T

:-) Dizzy

jeffgao wrote:
Quote:

Sometimes mine will want to get off the interstate then get right back on?

Well, in my area, this is the trick to save 15 minutes during peak hours. While the lanes are all packed with cars, the exit ramps are mostly empty.

Ha Ha. That's a good one if your on/off ramps aren't cloverleaf type & most of the crossroads aren't congested as well.

Around my area it would make a lot of people dizzier than they already are.

--
It's about the Line- If a line can be drawn between the powers granted and the rights retained, it would seem to be the same thing, whether the latter be secured by declaring that they shall not be abridged, or that the former shall not be extended.

NUVI

I LOVE MY NUVI 660

point A to point B or point B to point A gives different route

Interesting thread. My Nuvi 650T does sometimes find a route I would not have found otherwise. I've noticed that it will sometimes give a different route depending on whether I'm going to a destination or returning from it. Also, I frequently check the route that Google Maps shows before I leave then compare it to the Nuvi in-route. Gives me options.

Agree

Thanos_of_MW wrote:

Just yesterday, I had my nuvi send me south of a bottleneck (I was going waaayyy north of there) when I hit detour, on my way back from shopping. It did route me correctly going to the store when I hit detour, but not on the way back.

My destination was 3 miles north and it wanted me to go using a route I knew was ending in this intersection with the bottleneck (construction), so I hit detour again. It did use the same highway it gave me coming down there, so I thought it was OK, but NO. It took me south of the problem area and right into it with no way to get out, but going through it. This is why I'd love to see the "areas to avoid" feature available in all models, like the 8xx series. I was already aware of this construction area, and blocking this intersection would be something I would like to be able to do.

I agree 1000%, there ought to be an "avoid" function on these things.

I wish there was

an intersection avoidance or traffic light avoidance....

--
Striving to make the NYC Metro area project the best.

Interesting

TXRVer wrote:
akapauan wrote:
LaManchaDQ wrote:

I think it is learning my preferences and accommodating them.

I wonder if Garmin officially documents this somewhere. I too suspect there is some kind of historical data involved...

To a degree, this is true, I've never seen it documented, but it's provable. I know it applies to the nüvi 750, unsure about other models.

The algorithm used to calculate a route is the same whether in real time or in simulation mode assuming a traffic receiver is not in use and the ETA will be identical for either route. The ETA calculation is based on assigned speeds to road types.

I have the nüvi generate a route from my house to a point about 21 miles away that includes 13 miles of Interstate with a posted limit of 70mph. I then repeat in simulator mode and the duration to the ETA is identical. Here's where the adaptive learning comes in.

When using the nüvi, I normally tow a heavy trailer and rarely exceed 60mph on the Interstate. When the simulation has put me onto the Interstate, I switch to the odometer screen and the speedometer displays 58mph.

I thought this data might be coming from the track log, so I deleted it and repeated the experiment. It still showed 58 when I was on the Interstate. I then did a hard reset. It then displayed 70mph on that segment of the route and shorted the duration to the ETA. After a 300 mile trip that included some Interstate miles, a repeat of the same simulated route used before showed 61mph.

My conclusion is that the table of speeds stored in the nüvi to calculate an ETA becomes modified over time by the real time data it collects. For example, if you were to commute from home to work and back on the Interstate every day, and there was always a backup on that road such that you averaged 45mph over the course of some time, the nüvi would adapt to that speed for that type of road. When you later let it calculate a trip based on speed, it may take you off the Interstate favoring a different road type that would presumably get you there sooner. If this were true, then a hard reset would produce a route that favored the Interstate.

One caveat: Before doing a hard reset, be sure to have your Favorites backed up and some other settings such as keyboard type will go back to factory default.

I find both your theory and actual testing interesting.
Thanks for sharing your results.

Nuvi

I have the opposite problem...I WANT to take the worse roads to a location but the Nuvi 260 doesn't distinguish between limited-access highways and secondary highways. I wish one could choose: "Backroads Only"!

What About Your Avoidances?

What happens when you choose to "Avoid Highways"?

NOOOOOOO!! Nuvi does NOT

NOOOOOOO!! Nuvi does NOT know better... I've done the same thing... used it on a short trip that I KNEW the way. Example... I live 4.4 miles from where I store my motorhome... 2.4 miles straight up one street, ONE TURN, NO STOP SIGNS and 2 miles on another street. Nuvi had me go zigzag... SIX TURNS and THREE STOP SIGNS. One tenth of a miles shorter but took TWICE as long!!! and it's set for Fastest NOT Shortest.

--
Rick Long Las Vegas, NV Garmin 855

NUVI Lost

We just returned from a 4800 mile trip from Texas to Ca. Befor leaving I updated to nhuMaps lifetime, Most of the trip went well untill I left Yosemite NP going to Reno. After an hour I pulled out the paper map and saw my NUVI routed me 75 miles out of the way and put me on the worst back roads. All mountains, curves and narrow roads. I don,t know if it was the new update at fult or the unit. From now on I'll keep a paper map handy..

--
FJM

Zoom Out to see route

fredjm wrote:

We just returned from a 4800 mile trip from Texas to Ca. Befor leaving I updated to nhuMaps lifetime, Most of the trip went well untill I left Yosemite NP going to Reno. After an hour I pulled out the paper map and saw my NUVI routed me 75 miles out of the way and put me on the worst back roads. All mountains, curves and narrow roads. I don,t know if it was the new update at fult or the unit. From now on I'll keep a paper map handy..

If I am in a new area I will zoom out to see the route NUVI chooses. If I do not like it I may put some interim stops to go in the direction that seems best to me.

I had something like that

I had something like that happen a couple of times in Utah.Tried to take me up some roads they even though they had street signs the roads were dirt and gravel and you could see they were not travel on much.I had off roads set to avoid.I suspect mapping problems.

--
Charlie. Nuvi 265 WT and Nuvi 2597 LMT. MapFactor Navigator - Offline Maps & GPS.

...

I don't trust mine 100%. Common sense is a must.

--
Michael (Nuvi 2639LMT)

Well said Cyberian75

Cyberian75 wrote:

I don't trust mine 100%. Common sense is a must.

Last weekend my Nuvi had me make a right turn that looked sketchy at best. After about 20 yards, I saw the road would be a dead end and a guard rail blocked the way.

I could see the road on the other side of the guard rail and followed it back to the road I had been on. I needed to just go about another 1/4 mile and I was on the road on the other side of the guard rail. I should have known not to make the 1st right, but Nuvi lemming syndrome temporarily took over. grin