As far as I know, they have never replaced a road with a bike path here in the US. Yes, they have widened certain roads to allow bike paths on either side of them, but those are few and far between, and in my opinion, there aren't enough of them. Yes, there are places where they have built bike only paths, but those have not replaced any existing roads. The only thing they have replaced is defunct rail road tracks that have been out of use for quite a few years (Rails to Trails). How do I know this? Because I've been an avid bicyclist since 1986. Matter of fact, there was a period of 10 years that I didn't have a car, but rather chose to ride a bicycle everywhere I went (and I was a monster when it came to bike racing. Been clocked at 66 mph going downhill, 53 mph while drafting off of a large truck, could hit 48 mph in the final sprints during races, and had a cruising speed of 20 to 25 mph. Have also ridden long distances, with the longest ride being from Jacksonville FL to Newport RI.)