Given all the EU bashing recently: That's something I really like. We share the driving licenses (classes, as in 'B' for cars) even. You're only touching axle

Given all the EU bashing recently: That's something I really like. We share the driving licenses (classes, as in 'B' for cars) even. You're only touching axle weight and distance, but I wonder if the max length (truck + trailer) is clearly defined? Are you allowed to have more than one trailer (here: Nope unless you're driving a tractor most likely)? I have a BCE ('40 tonnes', biggest you can get here) license, although it is currently inactive¹. Trucks continue to amaze me and I'd like to understand how different the world is over there. ①: Truck licenses have a renewal date here in DE. For people far above my age (my dad) it's something like "Every five years after you're 60" or something like that. For me it was "Every 5 years" from the get go and I haven't renewed it for quite some time. I still could get it back, but would need to visit a doctor (general health), optometrist (field of view test) and maybe redo a first aid course.