I don't think it's speed enforcement in most cases. It's usually people not wanting to deal with changing lanes to deal with the slowest traffic. For a while I

I don't think it's speed enforcement in most cases. It's usually people not wanting to deal with changing lanes to deal with the slowest traffic. For a while I would come up across a large number of vehicles inexplicably stacked in the left lane, with a huge gap on the right lane. Younger me would zoom up the gap and inevitably find a semi truck and someone passing it very slowly, and the left lane would close ranks because they thought I was a dick. Older me just stays in the left lane. edit: I'll move to the right when it's so obviously clear that I won't have to move back to the left. But it's really tedious to be weaving across the road with regularity to maintain a strict adherence to the keep right law.