We live in a small hamlet on a country road with no pavement. Our boundary goes right up to the road and we have a strip of grass next to the road which is constantly churned up by people parking there to go for country walks. The people who park there also damage our garden fence by opening car doors on to it and they park infront of our front gate making it difficult to access our front door up the garden path.
We have a variety of ornamental rocks around the garden left over from the last owners and I'm considering painting them white and positioning them on the grass to deter people from parking on the actual grass.
They wouldn't stop people standing on the grass for safety when a car passes and they wouldn't stop people parking next to the grass (they are low enough to allow most car doors to open).
Several of our neighbours have done the same, which was what gave me the idea. The grass belongs to us, not the council of highways. The road is wide enough for two cars also.