TBH it doesn't seem too safe for cars either. You couldn't possibly see deer or other animals until they had already jumped into the road. Any normal hazard like a car stopped for a flat or lumber that fell off a truck is more hazardous in this situation.
Honestly, these are not common occurrences in England. Cars that are stopped like this are required to post a warning triangle ahead, and lumber just doesn't fall off trucks (lumber isn't very common anyway as the country is mostly devoid of forests).
