Auto Reroute and Journey time
Up until I got a car with an inbuilt navigation unit (Navi System – 6P0) I was quite happy to have my TomTom 6200 stuck to my screen. However I have now started to use the in-built with Android Auto and the Tom Tom android app and aside from the missing route bar (many mentioned in here), I was curious to know if the 'rerouting' set to automatic actually worked - without the side bar I just do not know. And after being trapped in Birmingham at 10pm last week for an hour I am deeply sceptical.
Another oddity I noticed that over quite a distance (at night so minimal traffic) Tom-tom and google maps can vary by up to an hour for arrival time – i.e. 250 miles from the south of England to Anglesey. Real odd.