I'd recommend Vancouver as a decent example of how segregated lanes can work in a North American city. That said, can you give specific examples of what you me

I'd recommend Vancouver as a decent example of how segregated lanes can work in a North American city. That said, can you give specific examples of what you mean by "make car infrastructure worse"? Usually segregation is just a matter of putting a barrier on an existing bike lane and painting lines, which doesn't actually change anything for drivers who stay in the lines. In some cases, a lane may be converted, but this rarely impacts travel times much for the same reasons adding additional lanes doesn't improve travel times. Vancouver did lots of traffic studies on this criticism in particular that you can read if you're interested.