C710 - Outbound/inbound routes differ?

[ticklepin]

I have noticed that my C710 will often suggest a route home different from that which it chose for the outward journey, even though the travel parameters are unchanged and no TMC in operation.
Has anyone else noticed this?
If this is a common finding, does anyone have suggestions why it should occur?

[GPS_fan]

This is common with most, if not all sat nav systems.

If the device thinks that a route may be only seconds quicker, it will try to navigate you that way.

Unfortunately, the device uses algorithms which work on a theoretical basis - whereas we, the driver, have to deal with reality.

Remember also, that the Mio is using speed limit and mapping information which may not be 100% accurate to calculate the best/fastest/shortest route.

I have exactly the same problem on a route which I travel frequently - the outbound and inbound routes are marginally different - but, luckily I know the are well enough to know to stick to the main road instead of driving down side roads with parked cars in the way or higher traffic levels on the alternative route.

My journey to work is under 50 miles travelling by my preferred route, but the shortest and fastest route options on the Mio both try to send me on a route which is over 60 miles.

Local knowledge and Via Points are a great help - you may like to take a look at a road atlas to see if there is any logic behind the different routes.

[Retty]

[ticklepin]

Thank you Retty.
On the occasions it has occurred I have not been aware of a one-way-street effect.
Where I have noticed a discrepancy is on journey to and from Kidderminster, from the south east via. M42.
Travelling west the device reasonably suggests using the B4188 after leaving the motorway at junction 1.
Returning, Thomas is seriously in error by suggesting a route through the centre of Bromsgrove!
I wonder if the algorithms could include a weighting for ‘undesirability’ of travelling through built-up areas.

Also Gps_fan’s observations rather surprise me.
I am generally very impressed by the Mio routing which I can only describe as ingenious.
That local knowledge should provide a route ten miles shorter than the ‘short’ choice in the parameters must be unusual.
I rather expected the application of the same algorithms to the same data to come up with the same result.
But of course, on the return journey, though the possible data must be identical, it is chosen and treated in reverse order.
Perhaps we should just be grateful that the devices are so frequently right!

[GPS_fan]

Sorry, I should have made myself clearer - my local knowledge and preferred route, which is 10miles shorter than the Mio suggested route takes me along A and B roads, but is one side of a triangle instead of the M and A roads suggested by the Mio, which are two sides of a triangle.

This routing is NOT unique to Mio and I am NOT complaining because timewise with a clear motorway, the 2 routes are pretty much the same - I just prefer the scenic route and travelling at an average speed above 50mph.

In some ways, the motorway is better - in other ways, the countryside is better...

Back to the routing differences -

the area where I see a regular discrepancy, depending on which direction I'm travelling, has nothing to do with one way streets.

However, I do think that it does take into consideration the position of road junctions and any slip roads on/off dual carriageway/motorway.

Having said that, v3.1 did try to route me the same way in both directions in this location, but I prefer to stick to a road where I'm not in danger of clipping the mirrors of parked cars every few feet.

I think you possibly know you're preferred route away from the centre of Bromsgrove and should perhaps follow your instinct instead of your Mio.

Out of interest, you may want to look at the ETA on your Mio for its route and the route it takes you in the opposite direction so that you can get a rough idea as to exactly how much quicker it thinks one route is over the other.

The one thing about sat nav which should give real peace of mind is that you should never get totally lost.

No sat nav is perfect, but the Mio gives you a hell of a lot for your money compared with some of the other brands out there.

[GPSBear]

My observation on this one is that it would appear, if the two route distances are roughly equal, to take the one with fewer right turns.............
_________________
Mio C710 on MioMap 3.3

[MaFt]

[GPS_fan]

On a lighter note:

I've had to give directions to a customer at work and then give them different instructions because they could only turn left

another customer - a psychic / clairvoyant was stuck in a traffic jam on the M25 and phoned us to see how long she would be stuck in traffic

To coin a good old Yorkshire saying - "There's nowt so queer as folk"

[ticklepin]

Thank you.
Very elegant; I don't think that I would ever have thought of that.

We really ought not to grumble too much!

[MaFt]

[GPS_fan]

I didn't mean to infer anything by my last posting.

GPSBear's comment about turning left reminded me of something which I thougt was funny and my Yorkshire quote was aimed at the people I'd referred to within that posting rather than anything other members had written.

Who needs TMC when you have a psychic like that in the car

Could you cope with sat nav if you could only turn left

Which menu is the turn left only option under

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