Originally Posted by Flying Lawyer

Ok, that way out of town. I normally get our of town via Kennedy-Damm.

However: The first mile if the A52 (between the ARAG Headquarters or the Renaissance Hotel and the Esso station) is a national road, the famous B1 leading from there all the way to Berlin and (in the past) going up to Koenigsberg. After the Esso station the B1 becomes A52 it continues to Essen, where it becomes the A40 and if you continue that way to Dortmund, as soon as the A40 reaches the Dortmund city border it becomes the B1 angain. The difference is easy: A national road can have crossings and traffic lights and there needs to be no shoulder (and there is a speed limit). Similar to the M and A concept in the UK.