That should indicate this is a German Autobahn. They have no speed limit (unless EXPLICITLY stated otherwise). One downside on the German Autobahn is that if you drive faster than 130 km/h, all your insurance policies related to driving are practically void. Your insurance policy must make sure that victims are compromised, though, but will gain the right to get all the money back from you, which is quite a debt you'll get. But hey, infinity is infinity, right :P