Map of Roman Roads in the UK
According to Business Insider, only 30% of the world's population drives on the left. However, in the UK, horse-drawn vehicles and pedestrians have travelled on the left-hand side of the road for centuries.
The reason behind this may reach as far back as Roman times. In 1988 in Swindon England archaeologists found a preserved track leading to a Roman quarry. The grooves in the road on the left were much deeper than those on the right. As carts would exit the quarry with a heavy load and enter it much lighter, this groove pattern suggested that Roman vehicles were already travelling on the left. So why was this system in place?
Most historians agree that travelling on the left hand side of the road grew from necessity and convenience.
As most people were right-handed, they may have felt safer travelling on the left, so that their right hand was facing any oncoming traveller. This was essential for self defense. It made sense to have your right hand closer to an opponent when confronted.
This consideration for self-defense is illustrated in the way spiral staircases were built in castles. These staircases were built so that those defending the castle at the top of the staircase had the advantage. When you are walking down, the left side of the step is wider and your right hand is away from the wall. When you are walking up, your right hand is against the wall, causing you to walk on the narrower side of the step.
Horses as Vehicles
Generally a right-handed rider finds it easier to mount a horse from the left side; this would be a reason to ride on the left. For safety it would be better to mount and dismount from the side of the road as opposed to the middle of the road.
Historians have found evidence of traveling on the left in Ancient Greece, Egypt and Rome. Troops were trained to march on the left side of the road, free to draw their swords with their right hand.
Customs and laws were established in Ancient Rome concerning transport and travel, to ease traffic congestion in the city. Vehicles were banned at certain times of the day and pilgrims were instructed by Pope Boniface VIII to keep to the left side of the road when visiting/traveling in Rome.
When Did Diving on the Left Become Law?
The General Highways Act of 1773 recommended that horse traffic should keep to the left of the road and this was included in the Highway Act 1835. By 1771 the number of coaches on the road had dramatically, making the choice of tracks even more important.
The Decision to Put the Driving Seat on the Right
Most British cars have the driver's seat on the right of the car but this was not always the case. When cars and motor vehicles were first introduced many had a central driving seat position, but soon manufactures began considering where the safest position might be. Some chose the side closest to the curb so that drivers could avoid collisions with objects along the curbside more accurately; others manufactured vehicles with the driving seat closest to the road to give drivers a good line of sight ahead. The latter consideration won out, and resulted in the driver's seat being installed on the right in cars in left-side driving countries such as the UK.
Driving in Other Parts of Europe
Most countries in Europe that became part of the British Empire used the keep-left rule, but over time many have converted to the right.
In 1792 a decree in France created a uniform traffic law requiring traffic to keep to the right, and Napoleon ordered the military to stay on the right. In Denmark, the system was adopted in 1793, and in Belgium in 1899. During the 19th century, the Netherlands, Switzerland, Germany, Italy, Poland and parts of Spain adopted the right-hand traffic system, to be aligned with France.
By law, Portugal changed in 1928, Italy in the 1920s, Spain in the 1930s and Madrid in 1924. Other counties switched over to right-hand driving in stages, Austria being a good example of this starting with the west in 1919 and finishing with Lower Austria in 1938.
There are currently only four countries in Europe where people drive on the left: United Kingdom, Ireland, Malta and Cyprus.
Changing Driving Side When Crossing Borders
Most counties that drive on the left are islands. The few that have borders with right-side-driving countries handle the changeover by using traffic lights, crossover bridges or one-way systems. Some manufacturers are experimenting with drive-by-wire and brake-wire vehicles which allow the steering wheel and brake controls to slide from left to right.
If Britain Decided to Change to Right-Side Driving
Would increase conformity with other countries and make driving abroad easier
Cost of the change: road markings, motorway junctions, signs
Vehicles with steering wheels on the left are often cheaper due to being mass produced.
Driving would be more challenging for drivers currently owning right-hand-drive cars. Their position in the road would change.
All drivers would need to make the change, so some may need to re-learn.
Buses, coaches etc. would be dropping off and picking up towards the middle of the road due to their door position.
Traffic lights with filters would need adapting.
One-way streets might need reorganizing.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2014 Ruthbro
John MacNab from the banks of the St. Lawrence on March 14, 2018:
Excellent article Ruthbro.