2598 - unreliable fastest routing

Kremmen · Posted: Wed Jul 15, 2015 1:29 pm Post subject:

I've always found SatNavs to be a tool to get you to your destination, eventually.

My original chunky TT1 from years and years ago did quite a good job of giving me a route from Heathrow to Malvern in 104 miles using almost the route I knew was the best. It did have a quirk of often trying to take me off a motorway for a single junction because an an A road was slightly shorter. You just got used to it and ignored it.

My built in Alpine unit used to take me round all the motorways and add 30 miles to the journey even though I'd asked for the shortest route. Once I'd turned off the M40 and aimed for the Oxford by-pass it recalculated and reduced both the distance and time so clearly an error in it's initial attempt.

The latest Alpine unit is lots better and is almost spot on so I've never used the Garmin for routeing.

From what I read here I think the frequent advice from sussamb is best, if you know the route and all you're looking for is an accurate traffic report then plot your route in basecamp, tweak it to suit, then load it in to the Garmin.
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BigJohnD · Posted: Wed Jul 15, 2015 2:31 pm Post subject:

Allan_whoops · Frequent Visitor Joined: Feb 18, 2006 Posts: 369

Its got worse!

In April we popped across to France and they had closed the Autoroute at Junction 31, the St Martin turnoff, heading down to Boulogne. Not a problem as that was where we were going.

Going there yesterday, it got us off at Junction 33 (two before). I assumed that the Autoroute was shut but then it got us back on it at the same junction.

This didn't happen before the last firmware and map update.

We also experienced the law of unintended consequences of P&O wanting a monopoly on the sea route!

sussamb · Posted: Wed Jul 22, 2015 9:48 am Post subject:

Allan_whoops · Frequent Visitor Joined: Feb 18, 2006 Posts: 369

No, it showed me that I would be exiting there as the the next instruction and then told me to take the exit well before we reached it. That's why I thought the Autoroute had been closed.

sussamb · Posted: Wed Jul 22, 2015 10:57 am Post subject:

Well I can't recreate that on my 2508 using 2016.10 so it was either a mad moment on your device or a left over traffic closure perhaps.
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Where there's a will ... there's a way.

Kremmen · Posted: Wed Jul 22, 2015 10:59 am Post subject:

I've often found that if there is a motorway junction on a left hand bend and the slip roads cut the corner and are actually shorter then on a shortest route option it will often do that.

The only routeing tool I've never managed to fool is Microsoft's MapPoint. That seems to get it spot on every time.
_________________
Satnav:
Garmin 2599 LMT-D (Indoor test rig)
DashCam:
Viofo A119 V3
Car Average MPG :

sussamb · Posted: Wed Jul 22, 2015 11:03 am Post subject:

Well it's not that on this occasion but it's an interesting theory, must say the two times it's happened to me that's not been the situation Smile

but then I rarely run 'shortest route'
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Where there's a will ... there's a way.

Allan_whoops · Frequent Visitor Joined: Feb 18, 2006 Posts: 369

Yes, it is! Remember, I was driving on the right not the left and the road 'appears' to be shorter. However, this really only stated about a year ago after an update. I ran into this with a ViaMichelin I had after an update where it used to 'think' that coming off at junctions was the quickest route.

sussamb · Posted: Wed Jul 22, 2015 4:26 pm Post subject:

Were you running shortest route? If not it won't apply, and in any case it doesn't work that way at that junction either in Basecamp or my 2508. Looking at the junction, and the roundabouts, it doesn't look shorter in any case.

I've now tested it using 'shortest route' and it still doesn't select the slip road, so it comes back to either a blip in your unit or an incorrect traffic incident.
_________________
Where there's a will ... there's a way.

inspiredron · Posted: Sun Aug 30, 2015 1:13 am Post subject:

Kremmen · Posted: Sun Aug 30, 2015 6:08 am Post subject:

With so many reports of this behaviour now being reported I wonder if Garmin are aware there is an issue?
_________________
Satnav:
Garmin 2599 LMT-D (Indoor test rig)
DashCam:
Viofo A119 V3
Car Average MPG :

sussamb · Posted: Sun Aug 30, 2015 6:59 am Post subject:

cwog · Posted: Sun Aug 30, 2015 10:01 am Post subject:

I have a memory of having a SatNav that had the ability for the user to set their most appropriate speed for each type of road, this technique enabled one to skew the resulting route to one's preferred type of route.

or

am I dreaming??

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