Weiß jemand, was die doppelt gestrichelten Linien in Deutschland bedeuten? Dieser hat sich für Dutzende von Meilen erstreckt.

It means „care, soon this line will turn solid and you wont be allowed to pass other cars anymore“.

Every time you see one, you have to yell „equal sign“.

That has no special meaning. Just the same as single lines with only some extra space in between. Can be done for different reasond. One reason might be one line changes soon to a solid line, an other reason might be some extra space between lanes for more security.