I don't think it has worked out properly as people just end up crashing into each other at the end of the NCZ.
The issue has just been moved further up the road.
I don't know how feasible it is but maybe randomising which f7 people go to. eg split the load between Duisburg, Dusseldorf and Koln. (I don't believe it could be done via the f7 menu but maybe with a /rep command to TP to a random local repair shop not a game dev but just throwing a suggestion out there)
alternatively move the F7 out of the city and onto the new 1.40 dual carriageway just outside the city, with slip roads. the biggest issue currently is that city does not have large enough roads to deal with the shear Volume of traffic by moving it to the dual carriageway, it is moving the traffic to a place which has the infrastructure, and reduces the volume of traffic as people are going to each location for 1 purpose not 2. (delivering load or repairs)