Driving – Germany & Austria

Driving the German roads and my first time driving a left hand drive vehicle apart from heavy earth moving machines scrapers and dump trucks. Scooting along the autobahns at 120 to 140km per hour and a lot of cars passing me like I was tied to a tree. I hate to guess what speed they were going.
Really have to keep alert with slower trucks and cars coming up fast and just as you are about to move across a lane something else comes zooming up behind you ready to do the same.
On one road we had a few tunnels with one of them being just over 9km long. Most tunnels we came across have an 80km limit. Some small towns we went through had a 30km speed limit and after sitting on 120km/hr plus for a few hours it seems very slow. I think I got pinged by a couple of speed cameras stategically placed where I would not see them.
We have also come across a lot of road works where speeds are reduced, and one section going in the opposite direction thank goodness was a line of maybe 8 to 10km of trucks and the last 2-3km of that line up they were in two of the 3 lanes.
Salzburg to Berchtesgaden was simple, barely even knew we were in Germany apart from a signpost saying so. But, when we went from Salzburg to Munich we passed through what must have been an old border patrol gate where everyone was slowed down to 20km/hr and a huge area where some vehicles were being hauled in for inspection by the several police there.
My last time driving on German roads was in an old 1958 Double Decker Bus called Woftam in 1983. My memory of it back then was that it was simple, but this time quit stressful. Maybe I just need more time and practice. Life was a bit slower back then.