Any ideas on keeping people from driving in my yard?

My yard is against the road and against the parking spots ( which is also used to put snow in the winter). So I'm constantly having people drive and park on the yard. I get that winter can make it a bit harder to tell where the grass meets the cement but it's literally destroying my yard. I thought about getting the orange stick markers but there just so ugly. Maybe big rocks every 7 ft or so. That's all I've come up with so any ideas on how to fix the problem without the ugly aspect would be appreciated. I live in alaska so most winters there is a lot of snow so it has to be visible year round so the loader doing the plowing can easily see what's there, thanks