Hank,
Sadly, you are right. I've seen the same thing going back 60 years. They key word here is "chasers." I don't chase. I scout the area a day or two in advance and go to my spot at least an hour early. I pick elevated locations where any cars that drive up at the last second won't obscure my shot and can be photo shopped out. Since 4014 has frequent service stops, you can get ahead to your next location. We just got back from the Cheyenne to Vegas segment and got anywhere from 4 shots to 1 shot per day, depending on the territory. I do walk in shots wherever possible. Even then some locals may show up. We had a Peruvian Indian sheep herder ride up to us near Altamont. He got off his horse, pulled out his cell phone and grabbed a shot. Unfortunately there wasn't any way I could put him in the photo as that would have been amazing!
Michael Allen