No worries, this isn‘t the first and also not the last time for such a proposal by a minority oppositional party. Politically this is not going to happen with most Germans relationship to their cars.
While you are right with the conclusion that it's not going to happen, you are wrong about who made the proposal. I suppose by "minority oppositional party" you mean the german green party (btw: more than 20% in recent polls) had nothing to do with it. The proposal actually came from the "Verkehrskommission" (English: transport commission), which is a commission of the federal government.