Imagine landing in London after years of driving in India. You step into a taxi and everything feels normal. Then imagine flying to Paris a few hours later and suddenly traffic lies flowing on the opposite side of the road. Here emerges an interesting thought: since automobiles are products of relatively recent invention, couldn't the entire world just decide which side of the road people should use?The reason behind such an unusual phenomenon is in the curious interplay of medieval battle strategies, colonizing powers, horse-driven carriages, politics, and economics.The history goes much further back than carsIn order to comprehend the traffic laws today, one must look centuries into the past, before the creation of the first automobiles. According to reports on HISTORY, researchers suggest that in the medieval period, most Europeans used to travel down the left side of roads and paths. Moreover, it is suggested that the Romans used the same strategy as it was evidenced by archaeological research. The widely accepted reason for this behavior lies in the fact that most people were right-handed and it was important to keep their dominant hand ready for greeting, protection, or drawing a weapon if necessary.In those times, travelling down roads could be dangerous, and many travelers could have weapons at their disposal. In such a situation, knights carrying swords on their left hip would find it easier to draw them using their right hands when meeting another person. To sum up, the first-ever traffic law was probably related to protection rather than transportation itself. Left-side travel made official in BritainFor a long time, the conduct on roads was dictated not by any law but by customs. But as the number of vehicles grew, this started to change. Britain slowly made left-side driving official by enacting laws to that effect. Since then, Britain spread its rules along with its empire all around the world.That is why, for example, nations such as India, Australia, New Zealand, and South Africa are left-side traffic countries. They simply adopted the rules of Britain and changing them now would require a prohibitive amount of money. In essence, each left-side driving nation bears some remnants of British transportation history.Napoleon contributed to creating the other sideJust like Britain was involved in promoting left-side traffic, one person made a great contribution to the promotion of right-side traffic, and he was none other than Napoleon Bonaparte.There may be disagreements on some aspects, but it is universally acknowledged that Napoleon played a significant part in promoting right-side traveling in several European nations.Therefore, countries like France, Spain, and Italy were identified as nations that followed the practice of driving on the right side of the road.Consequently, we saw the emergence of one of the most persistent geographical contrasts. While Britain and its colonies drove on the left side, much of continental Europe preferred the right side.Wagon dilemma that transformed AmericaThe case in the United States was somewhat different. As described by historians, huge freight wagons became more common in the 18th century. In such wagons, there was no position where the driver could sit. The driver usually sat on the left horse and controlled the team using his right hand. It was much easier to observe approaching vehicles when everybody drove on the right side of the road.Right-side driving gradually established itself.In 1908, Henry Ford presented a new car called the Ford Model T. One of its peculiarities was the presence of a steering wheel located on the left side. This setup was optimal when traveling on the right side of the road. By the beginning of the 20th century, everything was decided in favor of American-style right-side driving.Why do not other countries make this switch?On the surface, switching lanes may appear like an easy task. Just redesign your road markings, add new signs and ask the drivers to get used to them. However, in practice, it may be one of the most difficult transportation ventures for any country.Each road sign, highway connection, traffic light, bus stop, parking lot, driving test, public transport route, and car will need to be adapted. Financially, the venture may cost a fortune of hundreds of millions of dollars.One of the best examples of lane changes is Sweden which changed the side of its roads from left to right in 1967 in the event called “Dagen H” (“Day H”). An interesting scientific aspectWhereas history provides information about how the rift started, there are also studies which investigate whether people have an innate bias for one direction or another.In the 2019 research related to pedestrian movement, scientists noted that roughly 70 percent of subjects felt instinctively inclined to move to the right when maneuvering around others. They believed that side preference might facilitate the process of movement in congested spaces.Nevertheless, this does not necessarily imply that the right side is better. Contemporary traffic management systems function due to consistency. Once the drivers acquire the pattern of movements, they operate equally well on whichever side.In today's world, about three out of four countries have motorists driving on the right-hand side, but the remaining few continue to do so on the left-hand side. However, since the majority of the world's population resides in some of these left-hand-driving countries like India, they continue following an ancient practice.An action taken by a horseback rider out of practicality hundreds of years ago now stands out as the most striking proof of how history continues to impact us even today. The next time you drive a car in a foreign country and find yourself moving towards the wrong side of the vehicle, just know that you are carrying forward the heritage of medieval warriors, imperialists, wagon drivers, and car owners from times long past.