Separated rail or river trails are definitely a plus for bike commuting. But infrastructure parallel to roads with frequent intersections and mid-block driveways isn't really that much different than riding on the sidewalk (with all the hazards that come with it).
This may be true in suburban USA, but at least in European cities, sidewalks are used by pedestrians. You have to be alert riding a bike, but it’s a far cry from attempting to weave through foot traffic. The narrower roads also allow for quicker traffic light cycles, which is nicer than waiting a few minutes to cross your average suburban US arterial.
