Staying put well inside the boundaries of road is never a good idea, even more so if the weather conditions are very poor – i.e. rain, snow and ice.
However, to the defense of the hitchhikers seen in this video, the man driving the dashboard camera-equipped vehicle was not only going too fast for the conditions of the road, but he also didn't even bother to slow down once he saw them signaling for a ride.
This proved to be a bad move, as you can for yourself in the video that follows.