Hi all,
The Elzener Berge
The Elzener Berge downhill section on the A3 Southbound was foremost famous for its accident rates. Beginning of the Seventies on avarage 350 serious incidents per year. This was due to the downhill gradient steepening over the whole lentght of the section. The downhill righthand curve kept this out of sight fro the unaware. This gave it it’s nickname “The Katzenbuckel”, (Cats back). From 1972 it was equaly famous for its multiple camera speedtraps hidden in the second and third overhead portals which earned the German state of Hessen in the year 2006 alone 19.000 speedtickets with a revenue of EURO 1,8 million. The 20th September 2019 the whole set-up was finally removed. Remember in the early days the Southbound A61 on the other Rhine bank was still under construction. So for almost all southbound traffic from Köln onwards this would be the first serious downhill. Novice truckdrivers, including myself, learned here to restrain themselves downhill, against a cost. 
source : Wiki: Elzenerberge
regards
Rolf