Aye Spartacus, that was my understanding as well.
Way back, in 1975, when the A9 was largely still single carriageway, I was heading south from Inverness and the traffic was horrendous, coming from Newtonmore to Drumochter it was solid both ways and crawling behind a plethora of caravans and HGV's. I was riding my 1953 AJS 18S loaded with my worldly goods and an Interplod came past down the middle and beckoned me to tag along! Very instructive, at "making progress", without any blue lights etc and without frightening the **** out of other road users, we parted at the Inverness-shire - Perthshire boundary at the top of Drumochter. Perth was another 2 hours away and in total that leg of the journey took 4 hours.
I'll put the Stradivarius away, and just hope to get the Duke out for some more canters in the near future. At present it's the five mile shopping run!

Good health, Bill