I ride on some of the county roads in a residential area near my barn. Most people, because I live in "horse country" are very respectful, slow down, move over, wave and smile. Others act like they don't see us, and that they have the right of way. Regardless of the motorist, we always move to the grass shoulder, or even into a ditch in order to get off the road.
The article was extremely sad. It's one thing to be ignorant about horses - you don't know that horses spook or you don't see them, so you don't slow down. It's another to purposefully nail a horse and rider because you think you rule the road. I cannot believe someone could get out of their truck and scream at someone who might be dead on the side of the road - someone they might have killed. If the rider had been killed, that would be called "murder," not just "endangerment." How could someone do that? People continue to blow my mind each and every day.
It is so important to realize that life, that of both you and your horse, is precious and can end at any moment of any day.