Why must you drive on the right side of the road in some countries and on the left side of the road in other countries?Investigate the question, and you find a lot of confusion on right versus left.But France didn't conquer England, so England kept its custom of driving on the left.About a quarter of the world drives on the left, and most of those countries used to be British colonies.In Japan, they drive on the left, too, but people usually stand on the left on escalators.wagons with several pairs of horses and to drive on the right side of the road.It was easier for the drivers to sit on the left and control the horses with a whip in the right hand, and it was safer if other vehicles passed on the left so the drivers could see the distance between vehicles.There are different explanations for the use of right versus left.In any case, Napoleon, a ruler of France, ordered people to drive on the right side in the early 1800s.France conquered many countries at that time, and so these countries drove on the right.There is also evidence that ancient Greek, Egyptian, and Roman troops used to march on the left side.In the twentieth century, there was a trend to the right.As recently as 1967, Sweden changed its laws.