Sudden changes in the road conditions give clues to it use. 1969 for the building of the dam at Lac de L'Hongrin preceded by the military 1939. I hope the military facility is a bit safer then Blausee. Like the one way system if you have a watch. Similar to that used on Kander valley and Isenthalerstrasse.
I've been on holiday in the region of Aigle and Leysin, but I never knew of this road. It was an awesome drive. I always wondered where you get your ideas for trips. Could it be the website Dangerous Roads? They use the same description fior this road as you do. I understand the part through the roughly hewn tunnel is only open on weekends in the warmer months, and every day during the summer holiday. I've seen that time-regulated one-way traffic before in Switzerland. it was in the Maderanental near Amsteg.
