For the DC metro I don't think pop will save any time. The only times I've seen a line at a turnstile there has also been a line on the stairs / escalator. Any

For the DC metro I don't think pop will save any time. The only times I've seen a line at a turnstile there has also been a line on the stairs / escalator. Any time saved from not waiting at the turnstile will just translate to an increased wait time at the stairs before you get to the platform. w.r.t. bus networks, the article is about the metro. But yeah, I'd agree pop is faster for buses. I think it was Italy where I took a bus once and there were several payment machines on the bus (not next to the front door) so you could board and then afterwards pay without causing a line out the door.