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Garmin: to-and-from directions

 

Hi,

Question for the Garmin users on this site. I don't think stating the model matters since I have seen this with different Garmin models.

When I ask for a route from A to B the Garmin takes me one way but if I reverse the route the direction are not the same. Most of the route is the same but NOT identical. Is it me or does your Garmin do the same thing?

Note: The Garmin is not setup to avoid traffic, construction or any other option that can affect the route.

is not leftist

According to previous discussions on this subject the general consensus is the Nuvi algorithm tries to avoid left turns when possible.

--
Garmin 38 - Magellan Gold - Garmin Yellow eTrex - Nuvi 260 - Nuvi 2460LMT - Google Nexus 7

limited left turns

but it seems the 3490's don't think twice about maki9ng a u-turn if you don't exclude it in the profile.

Avoiding lefts

flaco wrote:

According to previous discussions on this subject the general consensus is the Nuvi algorithm tries to avoid left turns when possible.

Interesting.

There are urban areas with no left-turn arrows on traffic lights, and some suburban areas during rush hour that have left-turn arrows but too much traffic wanting to go left, where I think that strategy makes a lot of sense as a timesaver, but it very much depends on the traffic situation.

Avoiding lefts

flaco wrote:

According to previous discussions on this subject the general consensus is the Nuvi algorithm tries to avoid left turns when possible.

Interesting.

There are urban areas with no left-turn arrows on traffic lights, and some suburban areas during rush hour that have left-turn arrows but too much traffic wanting to go left, where I think that strategy makes a lot of sense as a timesaver, but it very much depends on the traffic situation.

Different route A-B and B-A

In one posting it was pointed out that since when you go one direction you would use different Hwy exits and make different turns then you would be on the return trip. This would/could also show up as different mileages.

As for the Garmin having you avoid turns where prohibited, I don't think so. Mine had me make a right turn in downtown Guadalajara into a one way street going the wrong way!

--
Nuvi 855LMT and Nuvi 3790LMT

I have checked numerous A-B

I have checked numerous A-B routes and different return B-A routes and a large number of the different return routes had absolutely no logic whatsoever for using a different return route (e.g. left turns, U-turns, ramp access, stop lights, stop signs, etc., etc.). It's as-if Garmin has designed some B-A return routes to be different for scenic reasons! Could that be? The other reasons I've heard have all been debunked to one degree or another... I'd still like a logical explanation...

--
According to the laws of aerodynamics, bumblebees cannot fly. But the bumblebees, not knowing the laws of aerodynamics, go ahead and fly anyway...

Doubt it

koot wrote:

It's as-if Garmin has designed some B-A return routes to be different for scenic reasons!

I seriously doubt that Garmin takes into account scenic drives by itself. From all I've read on this forum, and my own experiences, this would be totally unlike Garmin.

--
NUVI40 Kingsport TN

My Ignorance On Algorithms

flaco wrote:

According to previous discussions on this subject the general consensus is the Nuvi algorithm tries to avoid left turns when possible.

I remember watching a prograam on TV awhile back showing how UPS operates. It indicated they,ve programmed the drivers route to limit the amount of left turns a driver makes.
Primarily for two reasons, it's safer to make right turns and economics. Making a left usually takes longer and uses more fuel while idling to make the turn. I don't know if this policy still holds true today, but that was the norm several years ago.

It would surprise me if Garmin incorporated that algorithm in their Nuvi's since they usually have three options, Fastest, Shortest, Less Fuel.
Having no knowledge about algorithms, I don't know if they could factor in reducing left turns for one particular mode and not the others modes.

--
Nuvi 660 2460LMT Sold My 765T

!

David King wrote:
koot wrote:

It's as-if Garmin has designed some B-A return routes to be different for scenic reasons!

I seriously doubt that Garmin takes into account scenic drives by itself. From all I've read on this forum, and my own experiences, this would be totally unlike Garmin.

David - Maybe you missed the explanation mark after my tongue-in-cheek 'scenic' comment!!!

--
According to the laws of aerodynamics, bumblebees cannot fly. But the bumblebees, not knowing the laws of aerodynamics, go ahead and fly anyway...

I think it is...

...something that Garmin does on purpose. It gives us something to talk about. grin

--
It is impossible to rightly govern a nation without God and the Bible. ----George Washington

Feature

It's a "feature" built into the code. wink laugh out loud laugh out loud laugh out loud

--
Tampa, FL - Garmin nüvi 660 (Software Ver 4.90), 2014.30 CN NA NT maps | Magellan Meridian Gold

that's my story and I'm sticking to it

muell9k wrote:

It would surprise me if Garmin incorporated that algorithm in their Nuvi's since they usually have three options, Fastest, Shortest, Less Fuel.
Having no knowledge about algorithms, I don't know if they could factor in reducing left turns for one particular mode and not the others modes.

One example I can give you from my Nuvi 260 and the 2460, there is a steakhouse restaurant 2 miles from my house, on my way there the restaurant is on the left side of the street, there is a median strip on the road I’m traveling, both units want me to ignore the first cut in the median entrance right where the restaurant is located, that would make me do a left turn, instead it has me drive to the next cut on the median and do a U-turn making the restaurant on my right.

--
Garmin 38 - Magellan Gold - Garmin Yellow eTrex - Nuvi 260 - Nuvi 2460LMT - Google Nexus 7

frequently observed

depending on the road options available, my garmin will select a different return route. Left turns, one way streets, exit choices all make a difference.

--
___________________ Garmin 855 / 2720 / Magellan Meridian Gold

Thanks for all the facts

Thanks for all the facts regarding my question.

The TV show Mythbusters had an episode to test the fact that delivery companies are always taking right turns to deliver their packages.
They chose 2 routes using the same destination. One route had all the normal right & left turns and the 2nd route had only right turns. Their finding were that the first route is shorter but the route with all the right turns was longer BUT had a quicker arrival time.

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