They did the same thing in Amsterdam. There were a lot complaints at the beginning, but the city became much nicer in the end. Immediate improvement was the reduction of noise. Studies have shown that there was only a 5% increase of travel time. For example, that would be 1 minute on a 20 minute trip. That is because the largest determinant of average speed are the intersections and not the maximum speed limit.
I notice this from within a car as well. Cars take forever and waste so much space taking turns, merging, switching lanes. The issue seems to grow exponentially with vehicle size as well; nippy small cars turn and navigate a lot better compared to American genital compensation trucks.