Are deviations from the default route retained and reused?

[beachcomber6]

In the post-Covid world, I drive much less and my TomTom Go is rarely used.
Last Sunday I drove north on the A21 and I was directed off just South of Blue Boys Services, utilising some very rural roads and rejoining the A21 north
of Blue Boys. This was due to an accident/vehicle on fire and the road had actually been closed. I only lost 10 minutes, so excellent work by the GPS.
On my return journey on the Monday, the GPS directed me to turn off at the point where I had rejoined the A21 the previous day.
I decided to stay on the A21 and was reassured when the journey time and mileage to go both immediately reduced, and there were no delays.
My question is, is this normal for the GPS to apparently retain in memory a route previously taken because of an emergency and present it as first choice, even though both mileage and journey time will be higher?

 

[Willy875]

A GPS calculates the best route it may be that for the return the best route is this one.

On the GPS have you tried to select an alternate route.

 

[beachcomber6]

Thanks Willy875.
You would hope the GPS would work in this way, but, assuming it did, the criteria for 'best' would surely be shortest and/or quickest?
But, before the suggested turn off point, expected arrival time was 15:59. When I ignored the turn-off, this changed to 15:50.
Expected distance also decreased.
I did not try to select an alternate route, just used the 'home' option and left it at that.

 

[Willy875]

On a route, your GPS takes into account the slowdowns and traffic jams on your route, so your GPS will calculate the best route for you.

 

[beachcomber6]

So why did the remaining time & distance of my journey change for the better when I effectively moved off the original route??

 

[Willy875]

There are always surprises between the route offered by the GPS and the route you follow via the road signs.

 

[beachcomber6]

very enigmatic, but not much help
I'm guessing you are on the payroll and this forum is a waste of space

 

[dhn]

@beachcomber6

First of all, we are all volunteers here. Since this forum seems to be a waste of space for you, why not just get lost and seek help elsewhere.

Good luck with that.

 

[canderson]

So why did the remaining time & distance of my journey change for the better when I effectively moved off the original route??

The routing algorithm can be a bit opaque at times. There are hidden penalties for certain turns, and road classes where certain classes may be deprecated (time penalties added). Sometimes a small road segment has been assigned an inappropriately lower class, and having been relegated to 'goat track' status, the device will try to avoid it. I've also seen the results of an improperly embedded turn restriction cause a longer route to be created. Unfortunately, while embedded in the map data, these are invisible to the user. I often find that it is once I am clear of a particular intersection that the time drops.

Another possible reason for what you see is a change in conditions which are updated to devices connected to the "Live" system every 2 minutes, after which the device may take another minute or so to recompute possible ETAs based upon different routes.

And no, I'm no more on the payroll than you are, so you'll want to be sure you've got that straight before beating us up here.

 

[beachcomber6]

Thanks canderson, that's helpful and interesting.
I'm going to take the advice and get lost now, which, if you think about it is classic advice on a GPS forum ....

 

[Arno]

I'm going to take the advice and get lost now, ....

Don't make any detours. ;->)