Changed routing behaviour of 520

[flyingfuzz]

When I first purchased my TT520 a year ago it would happily route between Chineham in Hampshire and Tadley by routing you along Cufeude Lane.

Now Caufeude Lane is a almost single track road with passing places.

Since then I have subscribed to map updates and several updates later If I now try to navigate this route it never routes me along Caufeude Lane and always takes me miles around. In fact if I drive this lane with a route planned then the TT does nothing, not even reroutes its as if you are driving off-road that is until about halfway along the lane when it will suddenly reroute.

Now this is not an issue with me I am a local who knows the back roads. But why has the routing changed? I never use Map Share so that’s out. Both TT route planner and Google maps also miss this road.

My thinking is how many other roads does the TT not route you down?
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TT520 running App 8.351 & map UK&I v845.26345
Using Traffic TMC (round pin) & PGPS speed cameras.

[DennisN]

Miles around?

MS Autoroute Express shows the route via A339/A340, 8.5 miles, 14 minutes (36.4mph).

Via Cufaude Lane, 7.7 miles, 15 minutes (30.8mph). At a guess, a single track road with passing places is not likely to achieve that travel time and speed if you meet something coming the other way and need the passing place.

That looks rather more like sensible routing by the device.
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Dennis

If it tastes good - it's fattening.

Two of them are obesiting!!

[flyingfuzz]

I agree with the prognosis. It is a better routing option (unless you are local and know the roads)


Tried using shortest route rather than quickest, same result. Why has this changed?

Satnavs are notorious for routing cars down impassable roads is there a new algorithm to stop this type of thing?
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TT520 running App 8.351 & map UK&I v845.26345
Using Traffic TMC (round pin) & PGPS speed cameras.

[philpugh]

Have you updated your maps with MapShare? If so - check the map carefully - there may be a modification which prevents routing down that particular route.
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Phil

[Andy_P]

I've had a bit of a play with this one...
Cutting down the variables, calculate an "advance planning" route from N51.29961, W1.05613 to N51.32507, W1.07449.

This should just be a fairly straight and short trip along Cufaude Lane and Locksbridge Lane.

However, the 'Fastest Route' calculated is 14 minutes 6.1 miles and makes a big loop around to the east, avoiding those lanes.





'Shortest route ' calculated is 19 minutes and also 6.1 miles.





But if you force the TT to go via Cufaude Lane by putting in a "via" at (for example N51.31152, W1.06808) the journey is only 5 minutes and 2.2 miles.





The routing algorithm is VERY keen not to go this way though. If you put the via point any further north along the road, (for example at N51.31767, W1.07204 or N51.31842, W1.07202) the route calculated goes back to travelling the long way round and has some ridiculous double-backs.

I haven't been able to find any gaps in the mapping to account for this, and it can't be an incorrect "time to travel" value for that road as that would show up in the calculated journey times.

So... two issues
1. Why does the mapping not want to send you the most direct route? and
2. Why does the system lie about the other routes being faster and shorter?

I've asked the question of TomTom, let's see if anyone comes up with a reason.

[flyingfuzz]

Andy P - way to go.

The interesting thing is if you travel down Cufaude lane with a route active all the information in the Status Bar disappears only showing the GPS signal strenght and speed. It does not reroute or tell you to do a U turn.

It will reroute when you pass Locksbridge Lane (which is a unmade-up green lane not a tarmac road like Cufaude Lane).

So as you say, why suddenly route you down this lane when you put a via in the right place. It will be interesting to see what TT say!
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TT520 running App 8.351 & map UK&I v845.26345
Using Traffic TMC (round pin) & PGPS speed cameras.

[Andy_P]

[pcaouolte]

I have seen this sort of thing before on the tomtom. On that occasion when looking at the road on Google maps the road appeared thinner than normal on the section which tomtom didn't like using. On this occasion the road also looks thin on Google maps around Andy's via point.

It must be something to do with the mapping properties for that road.
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Paul

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