Why Japan Drives on the Left

Japan drives on the left primarily due to a blend of historical custom and British engineering influence: Edo-period “keep-left” habits met British-built railways in the 1870s, establishing left-side movement that was later formalized in national traffic regulations. The rule has held nationwide since, with one notable postwar exception in Okinawa, which drove on the right under U.S. administration until switching back on July 30, 1978.

From Custom to Convention: The Roots of Left-Side Travel

Long before cars, Japanese cities developed a tendency for people and horse traffic to keep left. A frequently cited cultural factor is the samurai class, who wore swords on the left and found left-side passing reduced bumping scabbards. While this is more custom than law, it helped normalize left-side flow in crowded Edo (Tokyo), making “keep left” a familiar practice before modern transport systems arrived.

Railways Set the Template (1870s Onward)

Japan’s first railways, notably the 1872 line between Shimbashi (Tokyo) and Yokohama, were designed and operated with British expertise. Like Britain, trains ran on the left. Railways were the backbone of national mobility in the late 19th and early 20th centuries, and their left-running practice influenced road layouts, crossings, and public expectations. As vehicular traffic grew, aligning road rules with the dominant rail convention proved both intuitive and practical.

How It Became Law

Left-side travel was encouraged by local regulations in the Meiji era and gradually entrenched as motor vehicles spread. Over the early 20th century, national rules standardized left-hand driving, and postwar legislation reaffirmed it. Today’s Road Traffic Act preserves this norm, shaping everything from lane markings to vehicle design (with right-hand-drive cars and buses the default).

The Okinawa Exception—and the 1978 “730” Switchback

Okinawa was the major outlier after World War II. Under U.S. administration, the islands adopted right-hand traffic. After Okinawa’s reversion to Japan, authorities executed a meticulously planned, one-day transition back to left-hand driving on July 30, 1978—widely known as “730.” The operation involved reconfiguring road signs, bus doors, lane markings, intersections, and driver education overnight to bring Okinawa in line with the rest of the country.

Why Left Fits Japan’s Transport Ecosystem

Left-side driving didn’t persist by tradition alone; it aligns with the broader transport system. Rail runs on the left, the vehicle fleet is overwhelmingly right-hand-drive (optimized for left-side traffic), and road engineering—from highway interchanges to bus stops—reflects decades of left-side design. Safety campaigns, driver training, and logistics planning all assume left-side norms, reinforcing the status quo.

Key Factors at a Glance

The following list outlines the main reasons Japan drives on the left, organizing them from historical to practical considerations.

• Edo-period custom: A longstanding tendency to keep left in pedestrian and horse traffic reduced conflicts on crowded streets.
• British-built railways: From 1872, trains ran on the left, shaping expectations and infrastructure design nationwide.
• Legal codification: Meiji-era rules and later national traffic laws established and maintained left-hand driving.
• Systemwide alignment: Vehicle design, signage, intersections, and driver education all reinforce left-side norms.
• Postwar uniformity: Aside from U.S.-ruled Okinawa (1945–1978), Japan kept left throughout; Okinawa’s “730” restored uniformity.

Taken together, these factors show how custom, engineering, and policy converged to make left-side driving the enduring standard in Japan.

Common Misconceptions

It’s tempting to credit samurai etiquette as the sole cause, but the modern rule owes more to 19th-century infrastructure choices and 20th-century law. The samurai story explains cultural comfort with keeping left, yet rail policy, government regulation, and later automotive logistics are what locked the practice in.

Summary

Japan drives on the left because early cultural habits meshed with British-influenced railways, and the resulting pattern was codified in law and reinforced by nationwide infrastructure. The only major deviation—Okinawa’s right-side period under U.S. rule—ended with the 1978 “730” switch back to left, cementing a uniform standard across the country.

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. 

Did Canada ever drive on the left side of the road?

Driving in the left lane was the norm on the east and west coasts of Canada, until cross-country jaunts by automobile became more common and the need for standard cross-border traffic rules became more urgent. Central Canada and the prairie provinces had always followed the American practice of driving on the right.

Why does Korea drive on the right?

Korea, meaning the unified Korean peninsula at the time of the change, shifted to driving on the right after 1945 because the American and Russian military vehicles that occupied the roads were designed for right-hand traffic, a legacy of U.S. and French influence, which prevailed over the left-hand driving tradition inherited from Japanese colonial rule.
 
Historical context

• Japanese Influence (driving on the left): During its colonial period, Korea was under Japanese rule, and Japan itself drives on the left due to historical British influence and the construction of its first railway system based on the British model. 
• Post-WWII Transition to Right-Hand Traffic: After the end of the Second World War, Korea was divided into two occupation zones: American and Russian. 
  • American and Russian Vehicles: The presence of American-made and Russian-built vehicles, which are designed for driving on the right side of the road, directly led to the implementation of right-hand driving on the Korean peninsula. 
• Cultural and Political Influence: Countries influenced by the United States, France, or Germany generally adopt right-hand driving systems. Korea’s post-colonial alignment with these influences meant a shift away from its prior left-hand traffic system to the right. 

Summary
The change from left-hand to right-hand driving in Korea was a direct consequence of the American and Russian presence after the Japanese colonial era. The prevalent use of American and Russian vehicles, which were designed for right-hand traffic, directly caused the shift and solidified the right-hand rule for driving on the peninsula.

Why do the UK drive on the left?

The UK drives on the left due to its origins in the Middle Ages, when right-handed people kept left to keep their sword arm free for defense against oncoming strangers. This practice continued with horse-drawn carriages and was reinforced by traffic laws in 18th-century London to reduce collisions. Britain, resisting Napoleon’s influence, maintained left-hand traffic, which was then codified into law and spread to its colonies.
 
Historical Roots

• Self-Defense: Opens in new tabThe most popular theory for left-hand driving is rooted in the need for self-defense. Most people are right-handed, so traveling on the left allowed a person to keep their dominant right hand free to draw a sword or other weapon if a stranger passed by. 
• Horseback Riding: Opens in new tabWhen people rode horses, they would typically mount from the left, away from traffic. Left-hand travel also made it easier to pass another rider, keeping the right hand free to greet or defend against an approaching stranger. 

Evolution into Law

• Early Regulations: The practice was first officially enforced in Britain in the 18th century to manage increasing traffic congestion in places like London. A law was passed to make all traffic on London Bridge keep to the left. 
• The Highway Act: This “keep left” rule was adopted and formalized in the Highway Act of 1835, making left-hand driving mandatory and establishing the practice for the whole of Great Britain. 

Cultural and Political Influence

• Resistance to Napoleon: Napoleon Bonaparte’s conquests spread right-hand driving across much of Europe, as it was associated with democracy. Britain, however, continued its tradition of left-hand traffic. 
• Colonial Legacy: Britain’s left-hand traffic system was adopted by many of its former colonies, a practice that continues in various parts of the world today.