Nüvi 750 sometimes has a different return route?

 

Does anyone know what causes the nüvi to select an often significantly different route from point B to point A than it took to get from A to B? This is not due to one-way roads and I've even seen it sandwich the different section of the route between segments that use the same road/interstate in the opposite direction.

It never seems to be different by very much in the total distance or time, but it is certainly odd.

-Rob

job to home= 4 blocks north

job to home= 4 blocks north to highway heading south.
home to job= get off one exit early and take local road 1 mile to job.

the way garmin says is actually 1 min slower, since when i pass the exit and it recalculates it shaves 1 min off my time.

My guess is as good as garmin's routing software is, in 15 seconds, compututing all the posabilities.

I notice sometimes its not the best, even set at QUICKEST, it still like automatically looks at the shortest, direct route, then tried to look for highways close by to shave some time off, but i think it first looks for direct point a to b, then change factoring in how many minutes, highway speed will save

Traffic Sometimes

Traffic sometimes can change at certain times of day and Garmin will try to avoid it. I have noticed this even if I dont have Traffic as an avoidance.

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Dave_ Nuvi 660 , 760,1490LMT Wooster, Ohio

It's not traffic

My 660 does this quite often. No reason at all it just picks a different route. It is consistent though, and picks the different route always.

yea mine too always selects

yea mine too always selects the same different route.

Exactly the same but different

Yes mine selects it exactly the same but different always too.

--
"Those that stop and smell the roses, must realize that once in awhile you may get a whiff of fertilizer."..copyright:HDHannah1986 -Mercedes GPS - UCONNECT 430N Chrysler T&C - Nuvi 2598- Nuni2555 - Nuvi855 - Nuvi295W - Nuvi 750 - Ique 3600

Different Return Routes

The Garmins aren't the only mapping devices that do this. I see it quite often when using Microsoft Streets & Trips to plan a trip.

.

Think of it this way, you get to find alternate routes to get to the same place. Personally, I like this. You never know when your regular route is going to be trashed.

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******************Garmin Nüvi 1300T****************Member 6523*******************

Turns???

Left turns are slower than right turns. Maybe it takes that into account. smile

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GPSMAP 76CSx - nüvi 760 - nüvi 200 - GPSMAP 78S

Left turn avoidance

rabiedenharn wrote:

Does anyone know what causes the nüvi to select an often significantly different route from point B to point A than it took to get from A to B? -Rob

There were some lengthy discussions in the past that suggested that Garmin prefers right turns over left turns because right turns are safer. (you're not crossing traffic). I think that this may indeed be an element that gets considered by Garmins routing engine.

allthough, i have never seen

allthough, i have never seen garmin route a way for 3 rights instead of a left?

Right vs. Left

thrak wrote:

Left turns are slower than right turns. Maybe it takes that into account. smile

I noticed the "different way back" behavior and too believe it has something to do with the turns you have to make.

I'm going to test "shortest" and "fastest" setting and see if it does the same thing.

rights

I have come across that fact of the right turns to be quite true. ex was a hotel downtown Chicago it routed me to 3 right hand turns and 1 left turn where I made 2 rights and 2 lefts to get to the same spot.

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John_nuvi_

Is a right safer than straight?

johnc wrote:
rabiedenharn wrote:

Does anyone know what causes the nüvi to select an often significantly different route from point B to point A than it took to get from A to B? -Rob

There were some lengthy discussions in the past that suggested that Garmin prefers right turns over left turns because right turns are safer. (you're not crossing traffic). I think that this may indeed be an element that gets considered by Garmins routing engine.

I've thought about that one, but one of the more annoying suggestions that I never take would be right-left-right in preference to left-right-straight. (I think it's a dozen feet or so shorter wink)

-Rob

Return Route

It looks to me like a flaw in the way the the garmin calculate the distances. No matter if I put in shortest or fastest or the time of day, it always wants me to take the highway back (about 5 miles farther) instead of going the same way I got there. Navetech has the data base but the gps does the calculations (I think). I am waiting for an operating system update that fixes this, I hope.

different return route

My 660 will sometimes give a different return route, or even from day to day. I think this is due to traffic conditions though.

It seems to go clockwise!

I also noticed the difference in routes from A to B, vs B to A. In my case it seems to follow a kind of "clockwise" route. Imagine as if the center of a circle is in the middle between the 2 points, the route ends up being somehow clockwise.

Has anyone noticed anything similar?

At one point in time I thought, but haven't confirmed, that it tries to minimize left turns, and that would also explain the clockwise direction of the route.

--
GARMIN nuvi 760 sites.google.com/site/lschwabe/

.

Many of the units seem to prefer avoiding left turns.

;-)

Motorcycle Mama wrote:

Many of the units seem to prefer avoiding left turns.

But left turns are the easy ones...at least where I live smile

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------------------------ Phil Hornby, Stockport, England ----------------------               http://GeePeeEx.com - Garmin POI Creation made easy           »      

aside from the different

aside from the different routes, it has not been an inconvienience at all, i tried it once against my subject, only to find, it delayed me a few minutes, and then i know not to follow it in the future, if i didnt know where i was going, i could care less about a few minutes difference, i just wanna get there. if i know how to get there, i can care less what the directions are.

In fact all the time, i routinley go different routes always having it recalculating, no big deal, its job is from point A to point B, not worlds best short cut. mind you we all want this calculated in less than 5 seconds.

Left vs Right

Hornbyp wrote:

But left turns are the easy ones...at least where I live smile

But then there are those that have the steering wheel on the wrong side too.

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ɐ‾nsǝɹ Just one click away from the end of the Internet

Differing routes

I sometimes travel to the town of Fair Oaks (near Sacramento) to visit an office I support. I leave from my home base office in Yuba City and let the nüvi route me. I've noticed that, when I make the return trip, the nüvi routes me in a TOTALLY different way. It's really strange. I just go with it because I'm so totally directionally challenged that, for me, any route that gets me from point A to point B is a good one. wink

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GPSMAP 76CSx - nüvi 760 - nüvi 200 - GPSMAP 78S

Garmin Said and What I Think

Leaving my house the Garmin 750 selects the optimal route. Coming back it misses the first left turn which is the optimal route. It also misses the second left finally taking the third left which is about 1.5 miles out of the way.

Garmin said that it has to do with street coding and that it's "complicated". They wouldn't tell me what that meant. What I think is that it's a bug that they are unlikely to fix.