I have read all above comments but I can't get instruction sound from android phone to play through car speakers when radio is on. I have tried all the output options in the list but can only get instructions through car system when using Media streaming from phone. As listening to the car radio must be the source of choice for the majority of people I can't believe tomtom have failed to find a fix to the problem.
I paid for one month to try the app but won't be renewing if the imminent update doesn't fix this.
Even if the app was free I still wouldn't use it.