Why the United States Drives on the Right

The United States moved to right-side driving largely because early American freight wagons were operated from the left side, making right-hand travel safer and more convenient; states then codified “keep right” after independence, and the automobile era—especially left-hand-drive cars like the Model T—cemented the practice nationwide. This shift was gradual, beginning in the late 18th century and becoming uniform by the early 20th century.

What “switch” actually means in the U.S. context

Unlike countries that changed by decree on a single date, the U.S. never executed a sudden national flip from left to right. In colonial times, customs varied by region and road type, but as the new nation’s traffic grew—particularly with large freight wagons—right-side travel emerged organically and was then locked in by state laws. By the time automobiles proliferated, the United States was already a right-driving country; car design simply reinforced that status quo.

The practical roots: wagons, teamsters, and safety

On America’s early long-haul routes, drivers of big freight wagons (such as Conestoga wagons) often rode the left rear horse or stood on the left side to keep their dominant right hand free for the whip and better control. Keeping right gave those drivers the best view of oncoming traffic and helped them judge the clearance when passing left-to-left on narrow roads. This practice—widespread on busy interstate turnpikes—set a powerful norm long before motorcars appeared.

Early laws that codified the practice

To understand how the convention took hold, it helps to trace the legal milestones that turned custom into rule.

1. 1792: Pennsylvania’s law for the Philadelphia–Lancaster Turnpike required keeping to the right, often cited as the first formal U.S. “keep right” rule.
2. Early 1800s: States including New York (1804) and New Jersey (1813) enacted right-side statutes, spreading the standard along key commercial corridors.
3. Mid-19th century: Most states had keep-right provisions, normalizing the rule well before automobiles.
4. 1908 onward: The rise of the automobile, notably Henry Ford’s left-hand-drive Model T, meshed naturally with right-side traffic.
5. 1920s–1930s: Uniform vehicle codes and statewide traffic acts standardized right-side rules and signage across the country.

Taken together, these steps show a progression: a practical custom became local law, then state law, and finally a nationwide norm reinforced by industrial design and uniform traffic codes.

Why right-side driving stuck and spread

Several overlapping forces explain why right-side driving not only emerged but also endured and expanded through the automotive age.

• Freight-wagon ergonomics: Left-side driving position for teamsters made right-side travel safer for passing and collision avoidance.
• Post-independence identity: Breaking from British left-side tradition had symbolic appeal in the early republic, easing acceptance of the right-side norm.
• Legal reinforcement: Early turnpike and state laws codified the rule, aligning courts, insurers, and local enforcement around “keep right.”
• Automotive design: U.S. manufacturers shifted to left-hand steering by the 1910s; LHD gives drivers a better view of the centerline when driving on the right, creating a self-reinforcing safety logic.
• Urbanization and traffic growth: As speeds rose and streets grew busier, uniformity reduced crashes and simplified road engineering, signage, and driver education.

These factors created a durable system: law, technology, and safety incentives all pointed in the same direction, making right-side driving the clear, stable standard.

Common misconceptions and notable exceptions

No single nationwide “flip day” in the U.S.

Some countries (like Sweden in 1967) switched on a single day. The U.S. did not. It transitioned state by state from the 1790s through the 19th century, arriving at a de facto national norm before cars were ubiquitous.

It wasn’t only about opposing Britain

Political symbolism helped, but practical freight-wagon ergonomics and safety were the crucial drivers. Continental Europe’s post–French Revolution right-hand shift is sometimes mentioned in the broader global story, but the American move was driven primarily by local conditions.

Territorial exceptions

The U.S. Virgin Islands drive on the left—a legacy of regional practice in the Caribbean—despite most vehicles there being left-hand drive. Most other U.S. states and territories drive on the right.

How automobiles locked in the rule

Early American cars sometimes used right-hand drive, but the industry rapidly coalesced around left-hand steering by the 1910s. Henry Ford’s widely adopted Model T (1908) made LHD mainstream, which fits right-side traffic by giving drivers the best view of oncoming lanes. As vehicle speeds rose, the synergy between LHD and right-hand traffic improved safety, reinforced driver training, and informed highway design—from lane markings to intersection geometry—making reversal effectively unthinkable.

Bottom line

America’s switch to right-side driving was a gradual, homegrown evolution: practical wagon-handling habits prompted early state laws after independence; then the automobile—especially left-hand-drive design—cemented right-side traffic nationwide. The result is a stable, self-reinforcing system that aligns human factors, law, and engineering.

Summary

The U.S. adopted right-side driving because teamster practices on large freight wagons made it safer and more practical to keep right; states codified that norm beginning in the 1790s, and the rise of left-hand-drive automobiles in the early 20th century locked it in. There was no single national “switch day”—just a steady, state-by-state consolidation of a practice that fit American roads, vehicles, and safety priorities, with rare territorial exceptions like the U.S. Virgin Islands.

Why did the US decide to drive on the right?

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. 

Was the US ever a left-driving country?

The first keep-right law for driving in the United States was passed in 1792 and applied to the Philadelphia and Lancaster Turnpike. Massachusetts formalized RHT in 1821. However, the National Road was LHT until 1850, “long after the rest of the country had settled on the keep-right convention”.

Why did people switch to driving on the right?

The driver of the vehicle being on the interior side of the vehicle in relation to the road allows them to better judge distance from oncoming traffic which makes it safer. So by building the controls on the left hand side of the vehicle the side of the road driven on became the right side of the road.

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.