True but it's not just ride share cars. Someone in the comments pointed it out, it takes one simple mistake to create congestion, distracted driving, going too slow, breaking, looking for parking etc. That will slow down person number 2 and 3 and 4 and so forth

This happens a lot on THE LIE where traffic is bad before the cross island and than opens up and than slows down and than opens up. Usually behind every slow pileup there's miles of free space.