Fastest vs shortest on Garmin i3

noddy · Occasional Visitor Joined: Jul 07, 2004 Posts: 17

Has anyone else come across this anomaly? I have yesterday purchased a new i3 and so I'm just playing around with it at the mo.
I put in a search to add my girlfriends house in favourites then used that destination to mess around with preferences etc.
I pressed " start navigating" and then when I went back into "review turns" it revealed that it was taking me way off course....5 miles further in fact on a journey that is 19.5 miles.
I went into the settings page and reviewed the "route preference" in navigation and altered it to "shortest" and did a recalc. of the route to see how this altered things. It now came out with a much more sensible route (in fact the route I would personally take anyway) but amazingly when I checked "review turns again" the time taken was 24.2 mins which was 3.12 mins quicker than the fastest route.
So to abbreviate what I have written above the shortest route was not only shorter by 5 miles but also over 3 mins quicker.
I rang Garmin and the guy didnt have an explanation other than he didnt think anything was wrong. He explained that in "shortest" mode it may take me through cities and slow roads because it is searching for the shortest way to get from A to B and that on "Fastest" setting it is working out the average speed assuming that all the roads are driven at their respective speed limits and will therefore find the route that will get me there the fastest. That all sounds logical so why is it doing this on mine. I'm bothered that when I am out of my local area it might be taking me all over the place. Obviusly in areas I now I can override it using common sense. The guy at Garmin suggested that it wouldnt matter too much if I was in an area I didnt know because as long as it got me to my destination I would never know if I was travelling the shortest or quickest way or not!!!
Anyway has anyone else encountered this? I can give you postcodes to do the search if anyone fancies trying to replicate this

foc_reaper · Posted: Wed Mar 08, 2006 4:36 pm Post subject:

Welcome noddy.. I myself am a newbie to this also..

And was wondering the same thing... I found at the weekend (using Shortest) coming back from my girlfriends (Maidstone) going home (Essex) it wanted to take me the wrong direction to start with.. until I went against the directions and it recalculated, and then took me in the right direction..

I might try this tonight, and review the directions to find out where it wants to go..
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zogman · Posted: Wed Mar 08, 2006 5:39 pm Post subject:

the 'fastest' setting will take you on major roads whether they are on your direct route or not, in other words if there is a major road say 10 miles to the right (on a map) of the way you are going the i3 will direct you to that road...shortest takes you more directly to your destination but using smaller 'b' type roads...unless there happens to be a motorway going in the same direction...
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PaulB2005 · Posted: Wed Mar 08, 2006 5:46 pm Post subject:

So does this mean "Fastest" means the route with the fastest roads rather than the route that is the fastest "time-wise"??

zogman · Posted: Wed Mar 08, 2006 5:57 pm Post subject:

in theory yes if you on or very near a 'fast' road.....if you are in the middle of nowhere and the 'fast' road is to the left or right of the direction you are going ,you might go right/left/up/down to the fast road before you start going in your direction.. so initially you might spend a while getting to the fast road....hope that makes sense.
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noddy · Occasional Visitor Joined: Jul 07, 2004 Posts: 17

Thanks Zogman but I dont think that is right. Surely the computer calculates the "fastest" route based on average speeds assumed for various roads. I can understand it taking me out of my way by 5 miles if it has worked out that I will get there 1 minute or so quicker but why does it do that when the "fastest" route is still 3 minutes slower? Remember that these are not my times but the figures the i3 worked out. The Fast route was 24.8 miles in 27.34 minutes and the shortest route was 20 miles in 24.2 mins

Lester_Burnham · Frequent Visitor Joined: Oct 17, 2005 Posts: 618

Trajet · Posted: Wed Mar 08, 2006 6:02 pm Post subject:

Remember that the i3 'learns yours driving speed on various routes and after a few trips the ETAs become a bit more reliable.

zogman · Posted: Wed Mar 08, 2006 6:04 pm Post subject:

just quoting from experience ....a few times now the i3 tried to divert me about 5/10 miles to get to a fast 'a' road whereas i carried-on on a 'b' road because i knew the roads....
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Lester_Burnham · Frequent Visitor Joined: Oct 17, 2005 Posts: 618

Racing_Snake · Occasional Visitor Joined: Mar 01, 2006 Posts: 37

PaulB2005 · Posted: Wed Mar 08, 2006 6:54 pm Post subject:

Lester_Burnham · Frequent Visitor Joined: Oct 17, 2005 Posts: 618

noddy · Occasional Visitor Joined: Jul 07, 2004 Posts: 17

noddy · Occasional Visitor Joined: Jul 07, 2004 Posts: 17

This is getting wierder.
I have just tried to do the route again but instead of going to girlfriends house, go to her town using the "cities" option. I get the same result as before i.e. Fast route is actually still longer in distance and time and short route is quicker.
However if using the "cities" option I choose to go to the next village to her town (in other words exactly the same route but a couple of miles further by driving through her town) it comes up with the right result i.e. both the fastest and shortest routes are identical.
Unless anyone else can tell me that they have experienced the same I'll have to assume it must be some sort of bug in the system.

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