Bug in recomputing the route after forking on purpose to an other other route that you prefer.
For example in France from Sainte Foy lès Lyon (69110) near Lyon to Guillestre (05600) there are 4 main routes :
1) "Frejus" tunnel : the time is shorter by 15 minutes but the toll is 50 € higher (than the 3 other routes that have equal tolls) : this is not cost effective. I do not accept in most of the case to take this route, the only one chosen by the GPS. An other reason is that the number of cars allowed by hour is limited in the tunnel so you may have to wait up to an hours according the experience of some of my friends in summer. Also the turns/curves between "mont Genevre" pass and "Briançon" are bad and tiring. According ViaMichelin 295 km and 3h53.
2) "Lautaret" pass : higher (2000 m) than 3, 4 or 5, turns/curves are less bad and tiring than for 3, the best landscape, may be closed during several days by snow. This is my preference except when weather is bad or risk of snow. According ViaMichelin 255 km and 4h07.
3) "Bayard" pass : lower (1300) than 2, turns/curves are worse and more tiring than for 2. According ViaMichelin 265 km and 4h18. Or its variant cutting around "Gap" and going near "Saint Laurent du Cros" and "La Rochette". According ViaMichelin 267 km and 4h12.
4) "Croix-Haute" pass : lower (1176) the first to be cleared after snow. This is my preference when weather is bad or snowy or when there is very high traffic (less jam). According ViaMichelin 287 km and 4h20.
5) via "Chambery, Saint Jean de Maurienne and Galibier pass (instead Frejus tunnel)" is not a good choice : According ViaMichelin 289 km and 4h49 and the turns/curves between "Saint Jean de Maurienne and Galibier pass" are very bad and tiring...
As far as I know ViaMichelin use the same geographical data base as Tomtom but obviously not the same speeds...
On June 27 2019 at nearly 3 PM, I left Sainte Foy lès Lyon. I have taken the decision to use route 2. I arrived at Guillestre near 7 05 PM.
At the fork between 1 and 2, I take the direction "Grenoble" instead of "Chambery". The GPS accepted rapidly (but only apparently) my choice because it is not possible to go back on an high way.
In fact the GPS has computed that route 3 was the shortest !
Please explain why TomTom disaggree with ViaMichelin. And what duration and numbers of km TomTom compute for route 2 and 3.
After Grenoble, I forked to 2 against the order of GPS. It kept recomputing(?) and asking to go back up to 56 km from Briançon (some km after the upper part of lake Chambon) ! Obviously this is wrong : it should have truly and fully recomputed and found the new route (2) shorter probably 5 to 10 minutes after the fork. All this time hearing the (stupid) order to go back was VERY BORING...
Tomtom should implement
-a simple way to choose the route (as does ViaMichelin with up to 3 options) before departure,
-or during the travel, a way to force a fast and complete recomputation of a new route when the driver does not go back at X (eg. 3) possible turning places or during Y (eg. 5) minutes or after Z (eg. 8) km taking into consideration the chosen direction of the on purpose "error". To avoid disturbance of the driver by the need of an entry, this new route should be accepted by default after a delay : this is similar to GPS action when there is a traffic jam and it has found a shorter way. In other words, the processor should do as if an hypothetical passenger has chosen the existing function "find an OTHER route" and accepted it only if it start with the direction I have chosen (or if I have parked the car and done the same action as as this passenger, which is time consuming and not always practicable)...