Why Some Countries Drive on the Left

People drive on the left largely because of historical customs that were codified into law—most notably in Britain—and then spread through empire, trade, and engineering influence; today, roughly a third of countries (home to about 35% of the world’s population) still keep left, with no clear safety advantage over right-side driving. This article explains how that convention began, where it persists, and why some nations switched sides.

From horseback etiquette to traffic law

The roots of left-side travel predate cars. Historians widely note that in crowded medieval roads, riders kept to the left so that their dominant (typically right) hand and sword were toward oncoming traffic, a practical norm that lingered into the carriage era. As road networks modernized, governments began fixing customary practices into law. Britain formalized left-hand traffic with the Highway Act of 1835, locking in a standard that its far-flung empire would replicate.

Why right-side driving took hold elsewhere

Continental Europe largely went the other way. The French Revolution and Napoleon-era decrees encouraged keeping to the right, a standard that spread with French influence across much of Europe. The United States also gravitated to right-side travel in the early 19th century, partly because large freight wagons put the driver on the left-rear horse, making it easier to pass oncoming traffic when keeping right. Over time, this right/left divide hardened along historical and political lines.

Where left-side driving is used today

Left-side driving is concentrated in countries with British ties and in a few places influenced by early rail and road engineering decisions. Below are representative examples.

• United Kingdom and Ireland
• Australia and New Zealand
• Japan (influenced by early British-led railway standards, later applied to roads)
• India, Pakistan, Bangladesh, Sri Lanka
• Southeast Asia: Indonesia, Malaysia, Thailand, Singapore, Brunei
• Southern and Eastern Africa: South Africa, Kenya, Tanzania, Uganda, Botswana, Zambia, Zimbabwe, etc.
• Caribbean: Jamaica, Barbados, Trinidad and Tobago, among others
• Mediterranean islands: Cyprus and Malta
• Territories with unique histories: Hong Kong and Macau (left) adjacent to mainland China (right); U.S. Virgin Islands (left)

This is not an exhaustive list, but it captures the main clusters. In total, about 75 countries and territories drive on the left, representing roughly one-third of nations and around 35% of the global population.

Why some countries switched sides

Nations have occasionally changed to harmonize with neighbors, simplify cross-border trade, or align with vehicle import markets. Several high-profile switches show the practical considerations behind such choices.

• Sweden (1967): Switched from left to right in a meticulously planned “Dagen H” to match neighbors and reduce cross-border confusion.
• Iceland (1968): Followed Sweden’s lead the next year for similar regional consistency.
• Nigeria (1972) and Ghana (1974): Moved from left to right to align with right-driving neighbors in West Africa.
• Myanmar (1970): Switched from left to right abruptly; many vehicles remained right-hand-drive, creating visibility issues that persist.
• Samoa (2009): Unusually, changed from right to left to tap cheaper right-hand-drive car imports from Australia and New Zealand and to accommodate returning diaspora drivers.

Switches are expensive and disruptive, involving new signage, road markings, driver retraining, vehicle regulations, and public safety campaigns. Most countries therefore keep their inherited standard unless economic or regional pressures are strong.

Vehicles, visibility, and infrastructure

In left-hand traffic (LHT) systems, most vehicles are right-hand-drive (RHD), putting the driver closer to the road’s center line for better sightlines when overtaking and negotiating intersections. The reverse applies in right-hand traffic (RHT) systems. Everything from bus doors and tollbooths to headlight beam patterns and highway interchanges is optimized for one convention, which is why mismatched vehicles (e.g., RHD cars in RHT countries) can have practical drawbacks.

Is one side safer than the other?

There’s no robust, universal evidence that left- or right-side driving is inherently safer. Road safety depends far more on enforcement, infrastructure quality, vehicle standards, and driver behavior. Some studies have explored whether right-handed dominance could marginally favor LHT systems (because the driver’s dominant hand handles fine motor tasks like shifting in manual cars, or the dominant eye faces the centerline), but real-world crash outcomes are driven by broader road safety systems rather than side-of-road alone.

Border realities and exceptions

Countries often engineer elaborate solutions at borders where conventions meet—think flyovers and crisscross bridges—to switch traffic flow safely. Notable examples include crossings between mainland China (right) and Hong Kong/Macau (left). A few places maintain different standards due to historical autonomy or legal frameworks, demonstrating how deeply embedded these rules are in local governance.

Travel tips when switching sides

For drivers visiting countries with the opposite convention, a few habits can reduce risk and ease the transition.

• Rent a vehicle with the local steering configuration for better visibility.
• Use lane-keeping and navigation aids, especially at roundabouts and multi-lane turns.
• Practice in low-traffic settings and take extra care at intersections and overtaking.
• Follow local signage closely; painted arrows and reminders are common near airports and borders.

These steps won’t replace local knowledge, but they help counter muscle memory and improve situational awareness during the first crucial hours behind the wheel.

Bottom line

Left-side driving endures because historical custom became law and then infrastructure. British imperial reach, engineering choices (notably in Japan), and regional coordination cemented the pattern. With the costs of changing high and safety outcomes driven by broader factors, most countries stick with the side they know.

Summary

Some people drive on the left due to centuries-old customs formalized in Britain and propagated through empire, trade, and technical standards, with Japan a notable non-colonial adopter via early rail influence. About a third of countries—home to roughly 35% of the world’s population—still keep left. Side-of-road choice has no inherent safety edge; it’s primarily a historical and infrastructural legacy that nations rarely change unless strong regional or economic reasons arise.

Why did America switch from left to right driving?

America drives on the right due to colonial-era transportation practices, particularly the use of Conestoga wagons where drivers sat on the left horse to control their whip-wielding, right-handed lashing of the team, naturally preferring traffic pass on the left. This habit, along with a desire to separate from British left-hand traffic customs after the American Revolution, led to right-hand travel becoming the norm, later standardized in states like New York by 1804 and eventually by Henry Ford’s left-side steering wheel placement on the popular Model T.
 
Colonial Practices and Wagon Use

• Conestoga Wagons: Opens in new tabDrivers on large freight wagons, particularly the Conestoga, would sit on the left rear horse. 
• Right-Handed Control: Opens in new tabThis position kept the driver’s right arm free to use their whip to control the team of animals, leading to a natural inclination to keep to the right side of the road. 
• Clear Passing: Opens in new tabKeeping to the right allowed the driver to see the oncoming wagon’s wheels and keep clear of them, facilitating safe passing. 

Cultural Factors

• Rejection of British Custom: The widespread adoption of right-hand travel was partly driven by a desire to establish a distinct American identity, separate from British customs. 
• The Revolution’s Influence: The American Revolution cemented this divergence from Britain, with right-hand travel evolving from a colonial habit to a symbol of national independence. 

Standardization

• Early Laws: Opens in new tabThe Philadelphia and Lancaster Turnpike Road, established in 1795, was the first to mandate right-hand travel. 
• State Legislation: Opens in new tabNew York formalized right-hand travel on all highways in 1804, and by the Civil War, this practice was followed in every state. 
• Henry Ford’s Role: Opens in new tabThe mass production of the left-hand-drive Ford Model T in 1908 further solidified right-hand driving as the standard in the United States, as it became easier for drivers to see and overtake other vehicles. 

Why do some people drive on the left side of the road?

Some people drive on the left side of the road because of historical conventions, particularly the need for right-handed individuals to keep their dominant sword arm free when facing oncoming threats. This tradition was solidified in places like Britain with 18th-century legislation, while other nations, such as the U.S. and France, adopted right-hand traffic due to different practices like large freight wagons and the influence of Napoleon. Consequently, former British colonies continue the left-hand traffic custom, which has become a matter of national convention rather than inherent advantage.
 
Historical Origins

• Ancient Romans: Evidence suggests Romans drove on the left, likely to allow the right hand to wield a weapon. 
• Medieval Europe: Many societies continued the left-hand custom for safety, as right-handed individuals could keep their dominant arm near oncoming strangers. 
• British Legacy: In 1773 and 1835, the British government formally established left-hand traffic, which then spread to its colonies. 

The Shift to the Right

• Large Wagons: The rise of large, horse-drawn freight wagons in the U.S. and France in the late 18th century led to a preference for right-hand traffic. Drivers would sit on the left side of the wagon to hold the reins with their right hand and control the horses with a whip. 
• Napoleon’s Influence: Napoleon’s conquests spread the right-hand traffic rule to many parts of Europe. 
• Henry Ford: The design of the Ford Model T with the driver’s seat on the left solidified the right-hand traffic convention in the U.S. and other countries. 

Global Distribution

• Approximately 30% of the world’s countries, largely former British colonies like Australia, India, and South Africa, drive on the left. 
• The remaining 70% drive on the right. 
• The choice is now a matter of national convention, with no inherent advantage to either side. 

Why do the French drive on the right?

The French Revolution: A major shift occurred during the French Revolution when Napoleon Bonaparte’s conquests spread French customs across Europe. Napoleon’s decision to drive on the right side was implemented in many conquered territories, and this influence persisted long after his rule.

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.