That's where I notice them as well. I haven't seen it recently, but I recall a few years ago there was a highway around here (Denver) that was asphalt for the t

That's where I notice them as well. I haven't seen it recently, but I recall a few years ago there was a highway around here (Denver) that was asphalt for the two leftmost lanes with a concrete slow lane that semi trucks were supposed to drive on. Maybe Denver is particularly bad for concrete roads because our freeze/thaw cycles get really bad. We have so many warm days in the winter interspersed with cold days and freezing nights.