Most countries drive on the right-hand side of the road. Others, like Great Britain, drive on the left. In the middle we have countries like Sweden, who can't make their minds up. That results in confusing scenes like the one we see here.
The day before this picture was taken - September 3rd, 1967 - Sweden changed its driving laws. People were now required to drive on the right instead of the left. Not everybody got the memo, and there were a lot of crashes and near-misses that day.