Let’s be honest, this question is only phrased this way to appease the two-thirds of the drivers of the world that now drive on the right-hand side of the road. The real question, the question that deserves to be asked, is this: why did everyone else stop driving on the left?
老实说，这个问题（为何英国人靠左行驶）之所以这样问只是为了安抚全世界2/3靠右行驶的司机。事实上，这个问题的真实问法应该是：为何现在其他人都不靠左行驶了呢？
Taking the left hand side in traffic is a habit that goes back hundreds of years, possibly as far as the ancient Greeks, Egyptians and Romans, but certainly to an era when people habitually carried swords when traveling. As around 85-90% of humans are right-handed, passing on the right-hand side would leave carriage and cart drivers more open to attack from people coming the other way. Knights with lances, squires with knives, peasants with pitchforks, everyone had to be ready for a dust-up at a moment’s notice, and that meant keeping to the left so you could get a good swing at your assailants. Granted, this did mean they were more vulnerable to be attacked from the pavement, but no system is entirely foolproof.
靠左行驶的习惯可追溯到几百年前，大约远至古希腊、古埃及和古罗马时代，就是人们会佩带刀剑出行的时代。由于85%-90%的人都习惯使用右手，如果靠右行驶，四轮和二轮马车夫更容易受到相反方向的攻击。执矛骑士、佩刀乡绅或者抗耙农夫，每个人都得随时准备面对突如其来的袭击，这意味着靠左行能在关键时刻给对手漂亮一击。当然了，这也意味着他们更容易受到来自行人的攻击。不过本来就没有万无一失的方法。
In 1773, the British Government introduced the General Highways Act, which encouraged horse riders, coachmen and people taking their vegetables to market (while carrying swords) to drive on the left, and that was that. The Highway Act of 1835 later reinforced this, making it the law of the land.
1773年英国政府首次颁布了《普通公路法》(General Highways Act)，鼓励骑马者、马车夫和去集市贩卖蔬菜的佩刀行人靠左行。就这样，在随后1835年的《公路法》(Highway Act)中再次强调了这点，至此，靠左行驶就成了这片土地上的明文规定。
However, things were slightly different elsewhere. Russian authorities, for example, had already noticed that their people tended to favor the right (maybe swords are less of a worry if you have to wear heavy coats all the time), so their first edicts on the topic were that they continue to do so. The pre-revolutionary French were on the left, but having revolted, they moved over as part of a general reordering of all society, and when Napoleon took over the army and began invading nations, he ordered them to stay on the right hand side too. Popular myth suggests this was also because he was left-handed, but there were other advantages; it would prove unsettling for his enemies, it would show him to be a great military tactician, and it would irk the British. Perfect!
然而，世界上其他地方的情况稍有不同。比如，俄罗斯政府已经意识到他们的人民更倾向于靠右行（如果你每天都必须穿着厚重的大衣，或许就不会那么担心刀剑的威胁了）。所以俄罗斯政府颁布的第一条相关法案就是保持靠右行驶的传统。革命前的法国也是靠左行驶，不过革命后，作为社会重组的一部分，也改为了靠右行驶。拿破仑掌权后征服其他国家时也要求军队靠右行，据传，这也是因为拿破仑本身是个左撇子，不过靠右行确实有其他优势：可以扰乱敌心，可以展示他非凡的军事谋略，还可以激怒英军。还有比这更完美的吗！
Everyone else kept left, but with increasing traffic on the roads in mainland Europe, this began to cause confusion, and slowly, over the course of the next hundred years or so, the European nations began to move over too.
其他人还是保持靠左行驶，不过在欧洲大陆，随着陆上交通工具的增加，靠左行开始给人带来困扰，所以在接下来的几百年里，欧洲国家也慢慢转为靠右行驶。
Also, this divergent approach occurred at a time when the British and the French were very busy colonizing the world. Every country occupied by the Brits—like Australia, New Zealand, India and the West Indies—kept to the left, and the ones occupied by France moved over to the right. The Americas were split, with the new arrivals from Britain, Holland, Spain and Portugal keeping to the left, and the French colonies insisting on the right.
而且，这种分歧发生在英法两国忙于在全球范围内开拓殖民地的时候。英国的殖民地，比如澳大利亚、新西兰、印度和西印度群岛继续保留靠左行驶的方式，而法国的殖民地则靠右行驶。美国则被一分为二，法国殖民者坚持靠右走，而新来的英国、荷兰、西班牙和葡萄牙殖民者又保持靠左行驶。
However, two vehicles were about to force this situation to change. In the late 1700s freight wagons (including the great Conestoga wagons) became more and more popular, particularly in America. These were pulled by a chain of horses, arranged in pairs. The best place to sit in order to control these mighty beasts was on the back of the left-hand horse at the back, so you could whip the others with your right hand. With the postilion driver in position, the best way for one wagon to pass another without accidentally banging wheels was the right hand side of the road. And where the wagons went, everyone else followed. So driving on the right became more common.
然而，新兴的两种交通工具改变了这种格局。18世纪末期货运马车（包括康内斯托加式宽轮篷车）越来越流行，尤其是在美国。这类货车是由并排的两列马匹牵引前行。控制这些"大力士"的最佳位置是左侧最后一匹马的后面，这样才可以用右手挥动马鞭控制其他的马匹。由于是左侧驭马，为了防止两辆交错的马车车轮不小心撞在一起，最好的方式就是靠右行驶。马车往哪走，人们就跟着往哪走，所以靠右行驶就变得越来越普遍。
And then the motor car arrived. While original designs for cars put the driver in the front and center of the vehicle, it wasn’t long before the advantages of having the driver able to see down the middle of the road became clear. And in those countries where car manufacturing became an essential industry for export (America, this means you), right-hand-drive vehicles with the steering column on the left quickly became a worldwide norm, forcing relative latecomers like Sweden to give in and move over too.
接着出现了汽车。汽车最初的设计是安排驾驶员坐在车子的前中部分，不久人们就发现驾驶员要能观察得到中间路况才能便于驾驶。在那些以汽车制造为重要出口产业的国家（美国，说的就是你），靠右行驶的“左驾车”快速成为全球标准，迫使汽车业后起之秀如瑞典不得不放弃原本的设计追随国际趋势。
Although it’s interesting to note that this arrangement does favor the left-handed driver somewhat, as their dominant hand is the one that never leaves the steering wheel. A right-handed driver in a British car spends a good deal of their time steering with his or her right hand while fiddling with the gear stick with their left, which seems the safest way.
有趣的是这种安排确实很合左撇子的习惯，这样他们的优势手也就是左手就可以不用离开方向盘了。一个惯用右手的司机要开一辆英式汽车就得花费很多时间习惯用右手操作方向盘同时用左手控制变速杆，看起来不失为最安全的方法。
This may account for the relative popularity of stick-shift gearboxes in British cars to this day.
从这种方式也可以看出为何英式汽车至今仍偏爱手动变速器。
Oh and one last thing. In Japan, they historically drove on the left—partly by choice, partly because British engineers built their railway network to be left-hand drive—until 1945, when U.S. rule forced the Okinawa Prefecture to switch to the right. They returned to the left in 1978.
哦，还有最后一点。在历史上日本这个国家是靠左行驶的，部分是自己选择的原因，部分是因为英国的工程师把他们的铁路系统建成这样。1945年，美国统治了冲绳岛并强制当地改为靠右行驶，不过1978年又变回了靠左行驶。
