Someone in my office asked me about this, an experienced driver of 20years she had driven along the M1, a three lane motorway/highway, and stayed in the middle lane because she thought that was where she should be, lorries in lane 1, cars in lane 2 and fast cars in lane 3. She complained that many lorries sounded their horn at her. I had a good 30 minutes with her on lane discipline and the fact that lorries could not pass her on the left nor go into lane 3 and her 55mph was too slow for many, she took it on board but complained again a week later when she had travelled in lane 1 but had to travel at the same speed as the lorry in front of her because the volume of traffic was such that she couldn't safely pull into lane 2 to overtake.