Favoured routes?

[Enfrance]

We've only used our Start 25 for a few journeys but already we've seen it give a preference for certain routes of 250km plus.

Each time we have travelled in a generally Western direction from our home in France our device has sent us on the same route for the first 50% or more despite the destinations being up to 100km apart. By comparison Google and Mappy have suggested other more direct routes although presumably the choice of type of route will make a difference.

The non autoroute option we use on the device sends us into uncharted areas which is fine with us but we are struck by the fact that we have now travelled towards our destinations on the same route until a certain moment and then suddenly been sent in a direct route in the last 75% of the journey.

Any comments would be interesting :thumb:

 

[dhn]

I presume your model has IQ routing. Do you have the latest map? And what other preferences are available to you under Planning?

Also, remember that local knowlege always trumps any GPS unit under certain circumstances.

 

[Enfrance]

yes, we have IQ routing and the lastest map. I've set up the planning options to 'ask me' in most cases.

It will be interesting in the next couple of weeks when we hope to take a short trip down to the Spanish border to see if it guides us due West and then South.

To be fair, we have been very impressed with the way it can find routes we would not usually take to places we often visit. In particular during the holiday season when many towns around here are very busy.

 

[Andy_P]

I think it must be coincidence that the routes you've asked it to calculate so far, must just happen to be fastest using these same roads each time.

Don't forget you can use the "Plan route" and "show route demo" features to try out any journey without having to actually go out on the road at all.

So you can try these other destinations any time you like.

 

[canderson]

IIRC, some of these newer units have some pre-planned route segments stored to speed up the routing process for longer trips. I wonder if that's what the OP is seeing?

 

[Andy_P]

IIRC, some of these newer units have some pre-planned route segments stored to speed up the routing process for longer trips.

There certainly was some marketing gumph about having pre-calculated millions of possible routes for quicker calculations, but as usual with TomTom it wasn't backed up with many hard facts.

But I thought they wee only there to help with the route planning. Very interesting if they actually use them in preference to the "proper" fastest route!

 

[canderson]

I wouldn't want to hang my hat on my assumption, that's for sure.

None of my 'longer' trips have had any ambiguity at all in routing. For example, traveling from Denver to Kansas City is a function of pointing the vehicle east on the equivalent of one of your "M" roads and sleeping for the next 600+ miles

 

[mvl]

App 10.x devices in the USA exhibit the pre-planned behavior.

They can do a full IQroutes calculation from Boston to LA in under 10 seconds.

On pre-App 10.x IQroutes devices, this type of calculation easily took a couple minutes.

 

[Andy_P]

App 10.x devices in the USA exhibit the pre-planned behavior.

They can do a full IQroutes calculation from Boston to LA in under 10 seconds.

On pre-App 10.x IQroutes devices, this type of calculation easily took a couple minutes.

Yes, but have you ever noticed it causing the sort of behaviour the OP is noticing?

...for certain routes of 250km plus.
Each time we have travelled in a generally Western direction from our home in France our device has sent us on the same route for the first 50% or more despite the destinations being up to 100km apart.
By comparison Google and Mappy have suggested other more direct routes

 

[mvl]

Yes, but have you ever noticed it causing the sort of behaviour the OP is noticing?

...for certain routes of 250km plus.
Each time we have travelled in a generally Western direction from our home in France our device has sent us on the same route for the first 50% or more despite the destinations being up to 100km apart.
By comparison Google and Mappy have suggested other more direct routes

Usually when that is reported, it is because the direct route is slower, or Tomtom thinks it's slower (eg: limited IQroutes history). I'd be curious to try to play around with the route, but I don't have an app 10.x device with a Europe map.