Here where I live we have lanes for bicycles on the major roads and on the bridges. I never came close to hitting one until they built the lanes. They are problematic because of cars making right hand turns. Bikes seem to always be in that blind spot and when you turn you might run it over. I'm aware but it has happened a few times with me and I've seen it a bunch of times. I don't know a solution but it makes a car driver seem to be making a right turn out of the middle or left lane. I don't know if we will ever be used to it. I haven't heard of anyone getting killed yet, so that's something.
Usually on the weekends there would be big herds of cyclists going down the streets. I usually just move to another lane or go around them when it's safe. One time I got stuck behind a herd in a construction zone and couldn't get around so I just slowly crawled along behind them, trying not to look at their glutes in those silly spandex shorts of theirs.
Our bike lanes are helpful in that I don't have swerve around them into the oncoming lane. We don't have very many as they would have to be paved on private home-owner property.
