I've noticed that many SatNavs tend to send you down roads which they deem to be the quickest way to your destination regardless of their suitability. These include single-track roads and routes which require turning off a main road, following a country lane then rejoining the same road a few miles ahead to save a few minutes, even if it involves wasting time making a difficult turn from a minor road onto a main road. I've been caught out by satnavs on a couple of occasions when I didn't know the area very well. In Cornwall I blindly accepted the satnav's suggested route, which entailed 10 miles of navigating single-track roads with lots of blind corners. On future occasions, it will be easier to refer to an A-Z! I've noticed Google Maps, TomTom and Waze are guilty of this. Surely there would be the demand for an option allowing users to avoid unclassified roads when planning routes should they wish? HGV satnavs (in theory) avoid narrow lanes, so in practice satnavs sold to car owners should have this option installed.