I assume that’s the law pretty much everywhere. That said, most of my troubles have been with people who speed by a lot and weave through traffic. Slower cars are less of a problem because while it might be the same speed difference, I see them much better and they usually don’t switch lanes erratically.

That said, I like traffic where I live now, because speeding 15% will get your license suspended, 30% will get you into jail. Traffic tends to be speedy, but coherent, everyone drives around the limit.