That's the practice here. We ride almost exclusively on no-shoulder roads. If we take long pulls, it's the lead rider's responsibility to check back for cars, then move left. That way, only one rider is exposed, not the whole paceline. That one rider can drop back into the line if a car comes while he's fading back. Thus we rotate the same way when we do rolling lines. We rotate the opposite way on roads with wide enough shoulders to accommodate two lines so that the fast line isn't pushed over into the part of the shoulder with more debris. If we are running a rolling line on a road with no shoulder and get a car back, we single up if it's not safe for the car to pass us. Pros and other teams can rotate any way they want. We try to keep it simple and consistent so everyone always knows what's going on and what's expected. Our motto is "safe and cooperative riding."