a poem by Henry Erskine
The rule of the road is a paradox quite,
The rule of the road is a paradox quite,
If you drive with whip or a thong,
If you go to the left
you are sure to be right,
If you go to the right you are wrong.
In 1300 A.D. Pope Boniface VII issued the first traffic ordinance when he instructed pilgrims on the way to Rome to keep to the left side of the road. By then, the custom of riding on the left was well established in Europe. (Old Roman roads excavated in England are rutted on the left.)
Most men were right-handed and wore their swords on the left hip. Riding on the left side of the road allowed them to respond more efficiently to threats from passersby. And with a scabbard bouncing on the left hip, the most comfortable way to mount and dismount was on the horse's left side. Furthermore, if a rider had to dismount on the road, doing so away from traffic was safest.
By 1771, one thousand hackney coaches traversed the narrow streets of London. By 1815, one and a half million people called that city home--most of them pedestrians. As the population and street traffic grew, accidents became the norm. Something had to be done to regulate the chaos.
Parliament passed a law in 1756 directing traffic on London Bridge to keep left. In 1771-72, it applied the rule to Scotland and added a fine of 20 shillings for disobedience. Lancashire passed a law on August 6, 1795 stipulating that carriages keep left.
Meanwhile, across the pond, Americans were also driving on the left side of the road. That changed with the Revolution. In 1792, Pennsylvania passed a law directing traffic on its turnpike to keep right. New York followed in 1804 and New Jersey in 1813. Canada was a mix of right and left hand driving according to province until the 1920s.
In 1794, France changed from left to right hand travel. Until then, the carriages of aristocrats bore left, while peasant foot traffic kept to the right. After the Bastille, that changed. Napoleon imposed the right hand rule on every country he conquered.
As for Britain, Parliament codified the "keep left" rule in 1835 and applied to all its colonies. Many of them--like India and Australia--still drive on the left side of the road.
Resources:
Carriers by Land, A Practical and Elementary Abridgement of the Cases Argued and Determined in the Courts of King's Bench
Treatise on the Law of Highways (US); 1857
Laissez-faire and Government Interference, Addresses on Educational and Economical Subjects; p. 67-68
