Hi multimob,
I'm sorry about the bus route relations. The seperate bus route around the market square is removed. And I'm not very familiar with relations. Is there an easier way to restore relationships (like the bus network) than selecting each street and adding a new relation. 
Thanks for the tips in advance, I will look into helping restore the bus network next.

As for the 2 lanes: from the Sint-Jozefstraat to the crossing with Heymanplein, they drastically reduced the space for cars. Now, it is only one lane (fietstraat actually) where the bus can ride together with designated traffic.