Why Some Countries Drive on the Right and Some Countries Drive on the Left

Driving MapToday I found out why some countries drive on the right and some countries drive on the left.

The origin of this varies based on the time period and country, but primarily throughout history people used the “keep-left” rule.  It has only been very recently that the world has predominately switched to the “keep-right” rule.

The first real archaeological evidence of a keep-left or keep-right type rule for a road, originates in the Roman Empire, which shouldn’t be surprising as they built a lot of massive, well trafficked roads spanning Europe and thus would have needed to establish certain rules governing how people were to interact on the roads.   So which side did the Romans use?  Archaeological evidence suggests it was common for the Romans to drive on the left side of the road.  This was first discovered in 1998 where a Roman quarry in Swindon, England had grooves in the road going away from the quarry on the left side that were significantly deeper than those on the right, due to the added weight of the stone.   It is not precisely known why they would have chosen this side, but it is probably similar to one of the main reasons this practice continued into the middle ages.

During the middle ages the roads weren’t always very safe for travelers; meeting people coming the other way on the road was something best done defensively.  Historians then believe the keep-left rule was adopted because, on a horse, if you were right handed and you met some unsavory company on the road, you could draw your weapon, typically attached to your left side, with your right hand and bring it to bear quickly against the person who is going the opposite way of you on your right; all the while, controlling the reigns with your left hand.  Then of course, if you happened to meet a friend on the road, you could more easily offer your right hand in greeting without needing to reach across your body when on horseback.  People on horseback then also typically ruled the road, so everybody else followed suit.

This keep-left rule was so common that, in 1300 AD, Pope Boniface VIII decreed that all pilgrims headed to Rome from wherever they were coming from should abide by the keep-left rule of the road along their journey.  This then held across most of the Western World until the late 1700s.

What ended up happening to force the switch in the 18th century were teamsters in the United States, who would drive large wagons with a team of horses, as the name implies.  These wagons tended to dominate the road and force everybody else to abide by the rule of the road they were using.  Very importantly, in many of those old, large American wagons, they did not include a seat on the wagon for the driver.  Rather, the driver would typically sit on the rear left most horse, when the driver was right handed.  This allowed them to easily drive a whole team of horses with a lash in their right hand.

This then forced the issue of having oncoming traffic on your left as the drivers would want to make sure any part of their team or wagon didn’t collide with oncoming traffic.  When sitting on the rear left most horse, this was much easier to do when using a keep-right rule of the road.  Just as important, if you wanted to pass a wagon in front of you, or at least see further down the road when you are sitting on the left side, it is much easier done if you are using the keep-right rule; this would give you much greater visibility of oncoming traffic when sitting on the left of your wagon.  Gradually, this system spread so that by the late 18th century, the first laws in the United States were passed, starting in 1792 in Pennsylvania, where the rule of the road was now officially a keep-right rule.  This quickly spread throughout the United States and Canada.

So how did this spread through Europe?  It started with France.  The reasons why the French switched to a keep-right rule instead of the traditional keep-left rule aren’t completely clear.  Some say it is because the French Revolutionists didn’t want anything to do with anything that had ever been Pope decreed.  Others say it was because they didn’t want to use the same rule of the road the English used.  Still others say it was entirely Napoleon’s doing.  The reasons why he may have done this, if that is the case, are even murkier ground.  Whatever the case, France switched to the keep-right system.  Napoleon then spread this system throughout the countries he conquered.  Even after he was defeated, most of the countries he had conquered chose to continue with the keep-right system.  The most important of these countries, as far as eventually further spreading the keep right system, was Germany.  Fast forward to the 20th century and, as Germany conquered countries in Europe, they forced their keep-right system onto those countries.

England never adopted this method primarily because massive wagons, as became common in the United States, didn’t work well on narrow streets which were common in London and other English cities.  England was also never conquered by Napoleon or later Germany.  Thus, they kept the classical keep-left rule of the road that had endured for hundreds of years before.   By 1756, this was actually made an official law in Britain.  As the British Empire expanded, this keep-left rule, as a law, spread throughout the world.  This hasn’t endured in most of the former British ruled countries, primarily thanks to Germany and the growing popularity of the keep-right system.  There are still a few though, probably the largest of which, by population, is India.

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Bonus Facts:

  • International regulations for preventing collisions at sea decree that all water traffic should keep to the right when two sea craft pass one another going opposite directions.  The reason for this was that historically the steering oar for ships was on the right hand side of the boat.  Thus, by passing each other port to port (keep-right), they would protect the steering oars from colliding as would have been possible had they adopted a keep-left rule.
  • In aircraft, the “rule of the road” is keep-right when passing oncoming air traffic.   Interestingly, in dual-control airplanes, the captain always sits on the left side of the plane as you might expect, but in helicopters, the captain sits on the right hand side.
  • Many early cars had the driver’s seat in the center of the car rather than on one side or the other.  Gradually, car manufactures began putting the seat on one side or the other.  Some chose to put it on the side closest to the curb so that people could more easily avoid scraping buildings, curbs, etc.  Other car manufactures would put it on the opposing traffic side to help reduce car to car collisions, which would tend to be more deadly.
  • Many early American motorized vehicles actually placed the steering wheel on the right hand side of the car, even though America used the keep-right rule.  This practiced finally was put to an end largely due to Henry Ford; he preferred the left side steering wheel.  Ford cars thus adopt the left hand side steering wheel.  Due to their popularity, this effectively squashed the right hand steering wheel cars in America.
  • According to research done in 1969 by J.J. Leeming, keep-left countries have a much lower collision rate than keep-right countries.  It is thought the reason behind this is that most people’s right eye is their dominant eye.  Thus, the right eye in keep-left traffic is the one closest to oncoming traffic and so should reduce collisions.   Another theory as to why this might be is that most people are right handed, so when driving a manual transmission car in a keep-left country, most people’s dominant hand is on the steering wheel; this could help in a person’s ability to maneuver accurately.
  • The people of Timor drive on the right in East Timor and the left in West Timor…  Ambidextrous drivers. :-)
  • Most horse riders and cyclists will naturally mount the horse or bike from the left hand side.  In the cyclist’s case, this is why most bike chains and gears are on the right side of the bike so that the rider can walk along on the left side of the bike and not worry about getting pants or shoe laces caught in the gearing while walking beside the bike.
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  • Another interesting factoid: when Norway changed from left-hand to right-hand driving they did so in steps. At first only cars and motorbikes changed to driving on the right hand side of the road, while trucks and buses were required to continue driving on the left hand side for an additional week.

  • When I was in East Timor (2000) everyone drove on the left (sometimes in the middle) side of the road. Perhaps your information is old, as it is possible that East Timor drove on the right prior to 1975 when it was a Portuguese colony.

    Also in 2009 Samoa switched to driving of the left-side of the road.

  • My understanding was that in pre-Revolutionary France, the aristocrats kept left and the commoners kept right. Come the Revolution, nobody wanted to look like an aristocrat for fear of an appointment with Mme Guillotine, so everyone started to keep right.

  • There’s something wrong with your map. Most Asian countries like Singapore and Malaysia drives on the right side, not on the left like what your map has suggested

  • In Stockholm, Sweden, there’s a quite intricate inter-change/junction which is in everyday called “Slussen”. This was constructed before Sweden switched from left to right-drive traffic and so was designed to be able to handle both ways.

    Perhaps it doesn’t sound interesting here, but if you ever drove a car in Slussen you’ll know why I find this a nice piece of interchange design…


  • Britain and India(because of British rule) drive on the left side. Old British bikes have the gear shift lever on the right side – This arrangement is correct for left driving countries because when you make a very tight U-turn on a bike (turning to the right), you occasionally place the right foot on the ground. Not having the foot on the brake means riders of left-shift Japanese bikes tend to grab the front brake in an emergency, toppling the bike.

  • @Jon: I don’t know about everywhere; but Malaysia and Singapore keep left.

    @Vivek: I don’t ride a motorcycle; but Japan keeps left. I would have thought Japanese bikes would be designed to cope with people riding on the left.

  • “Dominant” is the correct spelling, not “dominate”, as used twice in this article.

    • Daven Hiskey

      @Maire: Good catch on the “dominate” typo. I used it once correctly as the verb form, but used it twice incorrectly as an adjective, which obviously, as you say, is “dominant”, which is the adjective form of “dominate”.

  • …as in “dominant” eye and “dominant” hand. Also, the word is “predominantly” in the first paragraph, not “predominately.”

  • The reason the teamsters would ride the rear left horse, is that right handed people prefer to mount a horse from the left side.

  • David R. (Canada)

    I was led to understand that the French aristocracy started the keep-right rule when they adopted the idea of the driver sitting on the left horse in stead of the carriage. It enabled the passengers to get a better view, without looking at the back-side of the driver, and allowed others to more easily see the passengers.

  • In Japan, they go on the left because of the roads from when Samurai roamed. They carried their swords on their left side, since most were right-handed and in Japan if you were (and sometimes still) left-handed it was frowned upon as being incorrect and it would be force-corrected.

    As a Samurai, for someone to touch your sword meant that you would fight to the death. Samurai thus walked to the left so that swords would not accidentally clash. After the Samurai were gone, this continued to today where they still drive on the left.

    …this story may be complete bullshit, but it is what my japanese teacher told us and it makes sense to me.

    • I’ve heard this too.

      I will add that the reason that sword were so important to Samurai was that they were usually handed down from father to son, and also were believed to carry the samurai’s warrior spirit. It’s because of this that it was inappropriate to touch someone else’s sword (without permission) and to strike their scabbarded sword with yours was considered the same as striking the samurai himself.

      I’ve also heard that some young men spoiling for a fight would deliberately try to strike someone’s sword as they passed on the right.

  • every country’s generally accepted accounting laws dictate which side of a double-entry ledger is for debits and which is for credits. curiously, every country which drives on the left keeps their debit and credit columns on opposite sides from those countries which drive on the right.

  • @Jon, the map reflects which side of the road is used, not on which side of the car the person sits. Thailand, Singapore, Malaysia, Hong Kong, all drive in the left lane (keep left rule). Indonesia and Vietnam show as left and right respectively, but in my experience that’s only a suggestion, hardly a rule!

  • Regarding your answer as to why the “ride/drive left” rule was maintained in Medieval England. The correct answer is: The swords of knights were very heavy. You could not easily use it against someone on your right because you could not get momentum going with such a short swing (Inertia rules.) Also, you have the risk of cutting your horse’s head or neck if you swing at something on the right and miss. In battle a knight would prefer to swing his sword over the horse’s head and to the left. This gives a full 180º of arc or swing to gain momentum and no risk to the horse if you miss. So it is friendly for two knights to pass each other staying left. Neither can easily strike at the other. As for Romans, they followed the practice of Egypt and the Persians of the driver of war chariots standing on the right with the warrior or archer on the left. Take a look at any of the ancient depictions of such scenes and you will see what I mean…driver always on the right. The “why” if this practice may have something to do with the normative relative status of the driver and the archer. The driver was usually high status and the prejudice against “left” goes way back

  • Thankfully at least the article points out that driving on the left is the default position. Many ignorant people consider that Britain, Ireland, Australia, NZ etc. drive on the “wrong” side of the road. As many of us know, it is those who drive on the right side of the road who drive on the “wrong” side of the road, insomuch as driving on the left is, and always has been the default position in a world dominated by right-handed people.

    • Daven Hiskey

      @Kieran Tolly: While I personally don’t care about whether people drive on the right or left side, I’m glad the British still do if only so that when they complain about Americans still using the “Standard” system (derived from British units), rather than the Metric (which admittedly is in fact superior), I can reply with “We’ll switch to the metric system to go along with most of the rest of the world, when you go along with most of the rest of the world and switch to driving on the right side.” ;-)

  • Backing up Tim’s comments with regards to Timor, I was there in 2000 as well and we drove on the correct (left) side of the road and all of the local vehicles that I recall seeing were right (correct) hand drive.

  • Canada didn’t switch to the “right” side until the 30’s when cross-border traffic became hazardous.

  • For once and for all, the American way is the right way.
    Boats have always passed each other like cars on our traffic lanes, You get on a horse, drive a wagon and get in an American car from the left. Jousting is a good example of the “natural” side to pass a stranger. Besides, it puts the gear shift under your dominant “better” hand. BTW here in Pennsylvania one used to be able to tell if a farm was owned by a German or “English” family by the way their field was plowed. German plows through the dirt out of the farrow to the opposite side of English plows; something to do with not only the plow blade but were they put their strongest horse and what hand they preferred to hold the reins. Do you think it’s a coincidence that driving on the left makes people much, much less likely to import an American made car?

  • @Maire: If you’re going to be a rude know-it-all, why stop with one or two spelling errors to demonstrate how brilliant you are compared to everyone else? Go ahead and take your red pen to the whole effing site – we welcome the opportunity to be in the virtual presence of such genius. You could start with the use of “reign” instead of “rein,” which you must have caught since you’re so damn clever. I’m sure someday someone somewhere will be impressed enough by your smug superiority to have sex with you. Then maybe you’ll loathe yourself a bit less and be able to let the odd spelling, grammar, or typographical error slide LIKE THE REST OF US NON-ASSHOLES. Best of luck with that, jerkoff.

  • It’s obvious from the map that the countries driving on the left had strong British influences.

  • I liked the article, but last time I checked Australia still followed the keep left rule and was 2 and a half times larger than india. Unless your talking populations then India is larger.

  • Savoy Court (the road that leads to the entrance of the Savoy Hotel, London) is the only street in the U.K. where drivers are required to drive on the right. This stems from the early days of hackney carriages (that evolved into the black cab) where the driver would reach his arm out of the driver’s door window to open the passenger’s door (which opened backwards and had the handle at the front), without having to get out of the cab himself.

  • France & Germany changed the rule a few hundred years ago due to continued animosity towards England because they wanted to be ‘different’. As France & Germany are in Europe and all countries connected by road, the right hand drive side was adopted throughout.
    The hate factor among people of the three countries created changes. England changed the name of German Shepherd dogs to Alsations due to not wanting anything referring to Germany.

  • Just wondering that why Burma/Myanmar (former British colonial) is currently driving on the Right lane or Keep-Right system. Let me know if anyone know that. Cheers

  • This is a comment on an old post but I just found this site.

    You mention at the end that helicopters are the reverse of aeroplans in terms of seating. The answer to why that is is because fixed wing aircraft were developed in the US while rotary wing aircraft were developed in the UK primarily, hence the designers just followed what they knew!

  • I suspect there’s a practical reason horses (and thus bikes) are mounted from the left. A right-hand person will carry their sword on their left side to make it easier to drawn. Mounting a horse from the left means the sword hanging down doesn’t get in the way.

    The difference between planes and helicopters may have been simply to remind those flying what they were in. Another reason might have bee so the lead helicopter pilot is using his dominant right hand to control the more critical cyclic stick.


  • One morning in about 1967 the entire nation of Sweden switched from driving on the left to driving on the right.
    It is interesting to note that unlike Great Briton, which is insular, Sweden borders on Norway, which was already a drive-on-the-right nation prior to Sweden’s switch. This neccesitated some interesting traffic contructs at border crossings.
    There is very little info about Sweden’s switch in English, and this is essentially everything I know about it.

    • Oops! I guess the last time I checked was in 2005 when I “Alta Vista-ed” the subject.

      Now, there is beaucoup info out there in English about “Dagen H”.

  • Miguel de Althaus

    At present, even in France, trains use the left track and NOT the right one, It is the same in all the Continent!

  • In Timor-Leste (East-Timor), they drive on the left. Can’t speak for West Timor.

  • The reason there are right hand and left hand drive cars has nothing to do with the left or right rule.

    This issue has to do with royalty and specifically the King. Countries which historically had royalty and therefore a king would be forced to place the steering wheel on the left of the vehicle because no one was allowed to sit to the right of the king… no one.

    The design of automobiles stems from the design of coaches or carriages (horseless carriages) where this rule applied initially. In a royal coach, no one would be allowed to sit to the right of the king.

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