Why Most Countries Drive on the Right

Most countries drive on the right because of historical standardization led by France and the United States, reinforced by Napoleon’s influence across continental Europe, early American traffic laws, and the global spread of left-hand-drive cars in the 20th century. Over time, trade, cross-border harmonization, and vehicle manufacturing norms made right-hand traffic the default in much of the world. Today, roughly two-thirds of countries—and a similar share of the global population—drive on the right, while left-hand driving persists mainly in the United Kingdom, its former colonies, Japan, and a cluster of nations in Southern Africa and South/Southeast Asia.

From Horseback Habits to Highway Norms

Long before cars, traffic customs formed around practical needs. In Europe, many people historically kept left—think right-handed riders wanting their sword hand toward oncoming strangers. But practices varied by region and road users. In North America, large freight wagons pulled by teams of horses were often driven from the left-rear animal, which made passing oncoming traffic on the right safer and more predictable.

France’s post-Revolution push to “keep right” helped crystallize the change on the continent. As Napoleon’s armies and administration spread across Europe in the early 19th century, right-hand traffic became standard in much of his sphere. Once embedded in road codes and social habits, these conventions proved durable and self-reinforcing.

The Motor Age Cemented the Majority

The advent of mass motoring turned local customs into national—and then regional—standards. In the United States, early state laws mandating right-hand traffic meshed with the rise of the left-hand-drive automobile, most famously the Ford Model T. As cars proliferated, neighboring countries faced strong incentives to align with each other to ease cross-border travel and commerce. By the mid-20th century, much of continental Europe, the Americas, and China were firmly right-hand traffic.

Key forces that made right-hand traffic dominant

The following points summarize the main historical, industrial, and geopolitical drivers behind the global tilt toward right-hand traffic.

• Napoleonic-era influence: French decrees to keep right spread via Napoleon’s conquests and administrative reforms across continental Europe.
• Early U.S. practice and law: American freight-wagon traditions favored passing on the right; early state traffic laws codified it.
• Automotive design and scale: The global success of left-hand-drive cars (notably from U.S. manufacturers) normalized driving on the right.
• Regional harmonization: Neighboring countries aligned road rules to facilitate trade and cross-border travel, especially in Europe and the Americas.
• Postwar standardization: As road networks expanded, countries tended to match the side used by their largest trading partners and immediate neighbors.

Taken together, these factors created a powerful path dependency: once a critical mass of major markets used right-hand traffic, economic and practical pressures nudged others in the same direction.

Why Some Countries Still Drive on the Left

Left-hand traffic endures primarily due to history and continuity. The United Kingdom retained left-hand rules rooted in earlier riding conventions; its empire exported those norms to India, Pakistan, Bangladesh, Australia, New Zealand, and much of Southern and East Africa. Japan—never colonized by Britain—also adopted left-side rules during the Meiji era, influenced in part by British railway engineering and later kept them for roads. For island nations and regions with limited overland borders, switching sides offers fewer trade benefits and high transition costs, reinforcing the status quo.

Switches, holdouts, and the modern map

These examples illustrate how and why countries changed sides—or chose not to—through the 20th and 21st centuries.

• Sweden (1967): Switched from left to right in a meticulously planned overnight change (Dagen H) to align with its right-driving neighbors.
• Mainland China (1946): Adopted right-hand traffic nationwide; Hong Kong and Macau remain left due to distinct legal histories, with special infrastructure at border crossings.
• Newfoundland (1947): Changed from left to right shortly before joining Canada, aligning with the rest of the country’s right-side rules.
• Czechoslovakia (1939–1941): Transitioned to right under shifting control and regional pressures, matching surrounding continental norms.
• Samoa (2009): Unusually switched from right to left to tap cheaper imports of right-hand-drive cars from Australia, New Zealand, and Japan.
• Persistent left-side regions: The UK and Ireland in Europe; India, Pakistan, Bangladesh, Japan, Indonesia, Thailand, Malaysia, and Singapore in Asia; Australia and New Zealand in Oceania; and much of Southern/East Africa continue to drive on the left.

These cases underscore that geography, neighbor alignment, colonial legacies, and vehicle import patterns all shape whether a country stays left or right—and whether it ever changes.

Practical Realities Today

Modern road safety is less about which side you drive on and more about consistency, road design, and vehicle standards. Countries regulate steering wheel placement, headlight aim, and signage to match their side. Where borders meet opposite-side systems—such as between mainland China (right) and Hong Kong or Macau (left)—engineered flyovers and signage manage the switch. For car markets, trade ties still matter: nations tend to allow imports that match their driving side, keeping fleets aligned and reducing crash risk during overtaking.

Where right-hand traffic predominates now

The regions below broadly reflect where right-hand traffic is the norm, contrasting with left-hand strongholds.

• Predominantly right: Continental Europe (except the UK, Ireland, Malta, Cyprus), the Americas, mainland China, Russia and most of Eurasia, the Middle East, and much of North and West/Central Africa.
• Predominantly left: The UK and Ireland; South Asia (notably India, Pakistan, Bangladesh); parts of Southeast Asia (e.g., Indonesia, Thailand, Malaysia, Singapore); Japan; Australia and New Zealand; and significant portions of Southern/East Africa.

As of the mid-2020s, roughly two-thirds of countries—and a comparable share of the world’s population—drive on the right, with left-hand systems concentrated in identifiable regional clusters tied to historical influence and current trade patterns.

Bottom Line

Most countries drive on the right because early continental European reforms, American legal norms, and the global spread of left-hand-drive vehicles converged to make it the easiest, most economical choice—especially for neighbors and trading partners. Left-hand driving persists where history and geography made switching less advantageous, leaving a stable split that reflects centuries of politics, engineering, and economics more than any intrinsic safety difference.

Summary

Right-hand traffic became the global majority through a combination of French post-Revolution reforms, Napoleonic standardization, early U.S. laws, and the worldwide dominance of left-hand-drive cars. Regional harmonization and trade cemented the pattern across Europe, the Americas, and China. Left-hand driving endures mainly in the UK, its former colonies, Japan, and parts of Southern/East Africa and Southeast Asia, where historical ties and practical considerations have outweighed the benefits of switching. The result is a stable, historically shaped map where about two-thirds of countries drive on the right.

Why doesn’t the US drive on the left?

The United States drives on the right because right-hand travel was the norm in Colonial America due to the use of large wagons and practical reasons like ditch avoidance. This custom was codified into law, with New York making it mandatory for public highways in 1804, and it predates the American Revolution, not being an act of rebellion against Britain. 
Early American Practices

• Wagon Drivers: Opens in new tabIn the 18th century, large, heavy freight wagons became popular in the U.S. Drivers often sat on the left rear horse to better manage the team with their right hand and used their right arm to whip the horses, requiring them to keep to the right to avoid ditches and manage the whip more effectively. 
• Right-Handedness: Opens in new tabAs most people are right-handed, keeping to the right also allowed pedestrians and horseback riders to keep their dominant sword arm free for defense against potential threats on the road. 

Legal Standardization 

• Pennsylvania: Opens in new tabThe state of Pennsylvania was an early adopter of right-hand travel, legislating it for its turnpikes in 1792.
• New York: Opens in new tabNew York was the first state to prescribe right-hand travel on all public highways in 1804, establishing a standard that other states soon followed.

Distinction from British and Ancient Traditions

• Colonial Opposition: Right-hand travel in America was not an opposition to British rule but rather a separate path of development. Britain’s left-hand driving law was established in 1773, while right-hand travel had already become the norm in the American colonies. 
• Ancient Origins: While ancient Romans drove on the left, often to keep their sword arm free, early American practices diverged from this due to different transportation methods and societal needs, such as the need to manage large, four-horse teams with a driver seated on the left side of the wagon. 

Why do British drive on the left?

British drive on the left due to historical reasons, particularly the prevalence of right-handed people and the need to keep their sword hand free for defense when traveling on horseback in the Middle Ages. This custom continued with smaller carriages, where drivers sat to the right to keep their whip hand free. The practice was later formalized into law, with the Highway Act of 1835 mandating left-hand driving throughout the UK and solidifying it as a permanent habit.
 
Historical Origins 

• Medieval Times: In the days of knights and horseback riders, staying to the left allowed right-handed individuals to keep their sword arm free to defend themselves against oncoming strangers.
• Roman Influence: Evidence suggests that Roman soldiers also marched on the left, and some archaeological findings point to Romans driving carts and wagons on the left.
• Early Regulations: Pope Boniface VIII officially sanctioned keeping to the left for pilgrims visiting Rome in the year 1300, which influenced the practice in parts of Europe.

Transition to Modern Driving 

• Carriage Drivers: Opens in new tabWhen larger wagons and carriages with driver’s seats became common in the 18th century, the practice of sitting on the right to control the horses and keep the whip hand free further solidified driving on the left.
• Formalization into Law: Opens in new tabThe practice was legally enforced in Britain with the Highway Act of 1835, making left-hand driving mandatory across the country.

Why it Didn’t Change

• Cost and Habits: Changing traffic laws and associated infrastructure is extremely expensive and difficult, especially because habits are hard to break. 
• Continental Influence: The spread of right-hand driving in mainland Europe was largely due to Napoleonic conquests and French influence. Britain, resisting these influences, maintained its left-hand system. 
• Colonial Legacy: Britain’s imperial reach also spread left-hand driving to many of its former colonies. 

Why do some countries drive on the right side?

All of the countries that were part of the French Colonial Empire adopted RHT. Historical switches of traffic handedness have often been motivated by factors such as changes in political administration, a desire for uniformity within a country or with neighboring states, or availability and affordability of vehicles.

Why does Japan drive on the left?

Japan drives on the left due to its history with samurai, who kept their swords on their left hip, necessitating left-side passage to avoid collisions. This tradition was reinforced when British companies helped build Japan’s first railways in the 1870s, adopting British left-hand track practice, a system eventually codified into law for all vehicles by 1924.
 
Historical Roots

• Samurai Culture: Opens in new tabIn feudal Japan, most samurai were right-handed and carried their swords on their left hip. Walking on the left allowed them to pass others without their scabbards clashing, which was a serious provocation. 
• Public Adoption: Opens in new tabThis custom of left-side passage became a norm in society, and people would get out of a samurai’s way to avoid conflict. 

Influence of Railways 

• British Technical Aid: Opens in new tabWhen Japan began modernizing in the late 19th century, British engineers were instrumental in constructing the nation’s first railway system.
• Left-Side Trains: Opens in new tabThese railways adopted the British practice of left-hand traffic for trains and, later, electric trolleys.

Formalization into Law 

• Codification: The tradition of left-side driving, rooted in samurai custom and reinforced by the railway system, was officially codified into national law in 1924.

In summary, Japan’s driving on the left is a direct result of pre-modern samurai customs and the early adoption of British railway practices, which were later formalized into nationwide traffic law.