various speed limits are already imposed on many parts of the autobahn at certain times of day. not to mention you cant tell if the lighted speed limit signs are infact signs or radar with cameras. but instilling a flat top end is rediculous IMO. there isnt jack shit between dortmund and liepzig - thank god i was driving a mercedes! whoop, did i say that?
and between the two "interstate" systems, us and euro, i think the "interstate" autobahn is a copy of the Eisenhower system, but speed limits not used in various places in europe.
supporting the last statement, the no limit ideals of the autobahn is not only considered only on the "highway/freeway" like roads. autobahn, in germany, can be considered a well developed two lane as an extended stretch between two towns. basicly when ever you see the white circle with three bars and nothing inside.