Mysterious tank road sign in front of bridges: This is what it really means. The signs were placed along military-relevant roads during the Cold War.
They indicate the maximum total weight with which military vehicles are allowed to pass the bridge. However, the yellow signs are gradually disappearing from German roads. They have been gradually being dismantled for years. In East Germany this is not necessary at all, because according to Focus there were never any there. The MLC number above the double and single arrow shows the weight withwhich the crossing can be driven from both directions or only from one side.