[arethuza]

The A9 is actually pretty scary in parts because it alternates between dual carriageway and single carriageway and people have been known to get that wrong and thing they are on a dual carriageway when it is a single carriageway...

[ErroneousBosh]

I've done that and I've driven on the A9 hundreds if not thousands of times.

What's worse is that the inbuilt mapping in a lot of new cars think bits of it are 70mph dual carriageway when it's still single carriageway, and vice-versa.

[arethuza]

Same - driven up and down there countless times, but I still sometimes get alarmed on some of the dual carriageway parts where you can't see the other carriageway and I have a momentary panic of "This is a dual carriageway, isn't it?".