In 1998, archaeologists found a well-preserved track leading to a Roman quarry near Swindon, England. The grooves in the road on one side were observed to be much deeper than those on the other side, which would make sense given that carts would be driven without any load on the way to the quarry, but would return laden with stone. These grooves suggest that the Romans drove on the left, at least in this particular location.
In fact, some (e.g. C. Northcote Parkinson) believe that ancient travellers on horseback generally rode on the left side of the road. As more people are right-handed, horsemen would thus be able to hold the reins with their left hands and keep their right hand free—to offer in friendship to passing riders or to defend themselves with swords, if necessary.
The first legal reference in Britain to an order for traffic to remain on the left occurred in 1756 with regard to London Bridge. The Highway Act 1773 contained a recommendation that horse traffic should remain on the left and this is enshrined in section 78 of the Highway Act 1835.
In the late 1700s, a shift from left to right took place in countries such as the United States, when teamsters started using large freight wagons pulled by several pairs of horses. The wagons had no driver’s seat, so a postilion sat on the left rear horse and held his whip in his right hand. Seated on the left, the driver naturally preferred that other wagons pass him on the left so that he could be sure to keep clear of the wheels of oncoming wagons. He did that by driving on the right side of the road.
The British, however, kept to the left. They had smaller wagons, and the driver sat on the wagon, usually on the right side of the front seat. From there he could use his long whip in his right hand without entangling it in the cargo behind him. In that position, on the right side of the wagon, the driver could judge the safety margin of overtaking traffic by keeping to the left side of the road. Countries that became part of the British Empire adopted the keep-left rule too, although there were some exceptions. Canada, for example, where the maritime provinces and Vancouver (later to become British Columbia) drove on the left, eventually changed to the right in order to make border crossings to and from the United States easier. Nova Scotia switched to driving on the right on April 15, 1923. During World War II, American truck makers Ford, Chevrolet and Chrysler built 'Canadian Military Pattern' [CMP] trucks for use throughout the British Empire and most were right hand drive to use in left hand traffic countries.
On most early motor vehicles, the driving seat was positioned centrally. Some car manufacturers later chose to place it near the centre of the road to help drivers see oncoming traffic, while others chose to put the driver's seat on the kerb side so that the drivers could avoid damage from walls, hedges, gutters and other obstacles. Eventually the former idea prevailed.
In Europe, the 20th century saw a slow but steady shift from keep-left to keep-right. Portugal switched to the right early in the 20th century. Austria and Czechoslovakia changed to the right when occupied by Nazi Germany at the end of the 1930s, and Hungary followed suit. Sweden changed in 1967 and Iceland in 1968. Today, just four European countries still drive on the left: Cyprus, Ireland, Malta and the United Kingdom. All are island nations, and none shares a border with a country that drives on the right; all were once part of the British Empire.
Research in 1969 by J. J. Leeming showed countries driving on the left have a lower collision rate than countries driving on the right. This research is questioned in Peter Kincaid's book on the rule of the road, but some countries that have switched to driving on the right, such as Sweden), have seen their long-term accident rates increase by more than any increase in traffic volume. It has been suggested, but not proven, that this is partly because it is more common to be right-eye dominant. Traffic flows in a clockwise direction when driving on the left which enables right eyed people to use the right eye to see oncoming traffic. When overtaking (passing) on a right-side-driving road, the right-eyed driver looks in the wing mirror (side mirror) with the left eye and also views the oncoming traffic with the left eye which is not suited to the majority right-eyed people.
There are many instances of traffic having to change sides at border crossings, such as at those between Afghanistan and Pakistan, Laos and Thailand, Sudan and Uganda. Thailand is particularly notable in the context of border crossings, as it is the only sizeable country that has nearly all of its borders with countries that drive on the opposite side. It drives on the left, but 90% (4,357 km or 2,707 miles) of its borders are with countries that drive on the right, with only Malaysia driving on the left since Myanmar (Burma) changed from driving on the left to driving on the right in 1970.
Many borders are formed from natural barriers such as mountains or rivers, and this is particularly true of borders where traffic changes sides of the road, especially in Asia. These natural barriers make the number of border crossings much lower than would otherwise be the case. Furthermore, given their remoteness, most mountain border crossings have relatively low traffic volumes and so changing sides of the road is even less of an issue.
The four most common ways of switching traffic from one side to the other at borders are:
Some Commonwealth countries and other former British colonies, such as Australia, India and South Africa continue to drive on the left, but others such as Canada, Gambia, Ghana, Nigeria, Sierra Leone, and the United States have switched to the right. Other countries where driving is on the left are Thailand, Indonesia and East Timor in Southeast Asia, Suriname, Japan, the U.S. Virgin Islands and Mozambique. Like Hong Kong, Macau's traffic also moves on the left, in contrast with mainland China.
There is a popular story that Napoleon changed the rule of the road in the countries he conquered from keep-left to keep-right. The justifications mentioned are usually symbolic, such as that Napoleon himself was left- (or right-) handed, or that Britain, Napoleon's enemy, kept left. This story has never been shown to have a factual basis and it appears to be a legend.
The most common reason for countries to switch is for conformity with neighbours, as it increases the safety of cross-border traffic. For example, former British colonies in Africa, such as the Gambia, Sierra Leone, Nigeria, and Ghana, have all changed from left- to right-hand traffic, as they all share borders with former French colonies, which drive on the right. The former Portuguese colony of Mozambique has always driven on the left, since Portugal used to drive on the left until the 1920s. Mozambique didn't change (although Portugal did) as all its neighbours drive on the left, being former British colonies. Decisions by countries to drive on the right typically concern conformity and uniformity rather than practical reasons. There are historical exceptions, such as postilion riders in France, but such historical advantages do not apply to modern road vehicles.
In the former British Crown colony of Hong Kong and the former Portuguese enclave of Macau, traffic continues to drive on the left, unlike in mainland China, despite the fact that they are now its Special Administrative Regions. On the other hand, Taiwan, formerly under Japanese rule, changed to driving on the right in 1946 after the government of the Republic of China assumed administration; the same happened in Korea (both North and South), a former Japanese colony. However, some trains in Seoul, as well as pedestrian traffic in the subway system, still keep to the left.
All vehicular traffic proceeding in the same direction on any road shall keep to the same side of the road, which shall be uniform in each country for all roads. Domestic regulations concerning one-way traffic shall not be affected.Before that, a country could have different rules in different parts, for example Canada until the 1920s. Currently China forms an exception to this rule since the incorporation of Hong Kong.
When islands are excluded, the only continents in which the same rule of the road applies over the entire continent are the following:
In Australia this is the case with non-vintage (i.e. less than 30 years old) LHD vehicles, with the result that Australians who import such vehicles usually must pay sometimes thousands of dollars to convert them to RHD. The exceptions are for vehicles registered in Western Australia and the Northern Territory - both which have at various times hosted U.S. military facilities and had vehicles imported, used and sold by U.S. service personnel in circulation. The Australian Capital Territory (ACT) previously allowed non-vintage LHD vehicles to be registered, but changed its legislation some years ago.
In India, LHD cars cannot be sold commercially to customers, but they can be imported for research and testing purposes under government approval.
In New Zealand, LHD vehicles may be privately imported, and driven locally under a LHD permit. Since 1999, only LHD vehicles older than 20 years or cars owned and operated for at least 90 days may be privately imported. Diplomats and Operation Deep Freeze personnel are exempted from these restrictions.
In the Philippines, RHD vehicles especially cars, are banned. Public buses and vans imported from Japan are converted to LHD, and passenger doors are created on the right side. This ban was thought to be the result of the increase of accidents involving RHD vehicles, most of which were trucks. However, some vans keep their doors on the left side, leading to the odd (and dangerous) situation in which passengers have to exit toward oncoming traffic. Some RHD vehicles, like certain industrial cranes, remain.
Cambodia banned the use of RHD cars, many of which were smuggled from Thailand, from 2001, even though RHD vehicles accounted for 80 percent of vehicles in the country. The government threatened to confiscate all such vehicles unless they were converted to LHD, in spite of the considerable expense involved. According to a BBC report, changing the steering column from right to left would cost between US$600 and US$2,000, in a country where average annual income was less than US$1,000.
However, many used vehicles exported from Japan to countries like Russia and Peru are already converted to LHD. But even if the driver's position is left unchanged, some jurisdictions require at least replacement of the headlamps.
Singapore bans LHD vehicles from being imported for personal local registration, but temporary usage by tourists of LHD vehicles is allowed. However, diplomatic vehicles in Singapore are exempt from the RHD-only ruling, and there are a few hydrogen and fuel cell powered LHD vehicles currently undergoing trials in Singapore.
In Taiwan, Article 39 of the Road Traffic Security Rules (zh:道路交通安全規則) require a steering wheel to be on the left side of a vehicle to pass an inspection when registering the vehicle, so RHD vehicles may not be registered in Taiwan. This rule does not apply retroactively, so a RHD vehicle that was registered before this rule does not lose its registered status and may continue to be legally driven.
In Trinidad and Tobago, LHD vehicles are banned except for returning nationals who were resident in a foreign country and are importing a vehicle for personal use. LHD vehicles are also allowed to be imported for use as funeral hearses.
In West Africa, once-British Ghana and Gambia have also banned RHD vehicles. Their traffic has been changed from on the left to on the right. Ghana prohibited new registrations of RHD vehicles after 1 August 1974, three days before the traffic change on 4 August 1974. RHD vehicles may be imported only temporarily into Sierra Leone, for example for humanitarian programmes, but must be exported at the end of the operation.
Most of the above bans on RHD and LHD vehicles apply only to locally-registered vehicles. Countries that have signed the 1968 Vienna Convention on Road Traffic are not allowed to make such restrictions on foreign-registered vehicles. Paragraph 1 of Annex 5 states "All vehicles in international traffic must meet the technical requirements in force in their country of registration when they first entered into service". Therefore all signatory countries and most non-signatory countries allow the temporary import (e.g. by tourists) of foreign-registered vehicles, no matter which side the steering wheel is on. Oman, which has not signed the convention bans all foreign-registered RHD vehicles.
Both RHD and LHD vehicles may generally be registered in any European Union member state, but there are some restrictions and regulations. Slovakia, despite being a member of the European Union, does not allow the local registration of RHD vehicles, even if the vehicle is imported from one of the four EU countries that drive on the left (UK, Ireland, Cyprus, and Malta). Lithuania has prohibited new RHD vehicle registration since 1993.
Because blackout strips and adhesive prismatic lenses reduce the safety performance of the headlamps, most countries require all vehicles registered or used on a permanent or semi-permanent basis within the country to be equipped with headlamps designed for the correct traffic-handedness. In the UK, US government and military personnel who brought RHT/LHD cars with them used to 'trade' headlamp assemblies with a person returning to the US. The newcomer then had proper LHT lights and the US-bound returnee had proper RHT ones again. As most 50s-80s headlamps were interchangeable, this 'swap' could save motorists time and money.
Anecdotal reporters have observed the requirement to adjust headlamps for the traffic-handedness of the country is increasingly flouted, and is now rarely enforced by European police forces. In France, this may be due in part to the 1993 deletion of the previous requirement for selective yellow headlamp light; foreign-registered vehicles are now much less conspicuous at night.
Without sidecars attached, motorcycles, motor scooters, mopeds, and bicycles are almost symmetric with their handlebars in the centre. However, motorcycles are often equipped with automotive-type asymmetrical-beam headlamps that likewise require adjustments or replacement when brought into a country with opposite traffic-handedness.
Buses typically have passenger doors only on the kerb side, which severely restricts their ability to operate effectively on the opposite side of the road to that for which they were designed. Increasingly, touring coaches, which are likely to cross frontiers of traffic-handedness during their duties, are fitted with a door on the opposite side from the kerb, to simplify access and egress in the foreign country. In Britain this is known as a "continental door", since its usefulness will be in continental Europe. It doubles as an emergency exit, but is much more user-friendly than an exit designed solely for emergency use.
It is usually fairly straightforward to retrofit a non-kerb-side door on buses with relatively low floor height, for example the many traditional British double-deckers sold on for tourist use in the USA and Canada.
Trains may or may not adhere to the same directionality as cars. In France, for instance, cars keep to the right, but the first train lines were built by British engineers, so kept to the left. The Paris RER trains keep left, but have to operate on separate tracks within the Paris Metro area which was designed to run on the right. Another anomaly occurs in the Alsace-Moselle region, where trains keep to the right because the lines were built in the late 19th century when Alsace-Moselle had been part of Germany. Bridges at the former border allow the trains to swap sides. High-speed TGV trains, however, operate on dedicated lines which were built more recently, but they keep left because they interface with older lines. Madrid Metro trains operate also to the left.
Moreover the exceptions of left or right hand driving are much more common for trains than for cars. Initially, most steam engines were RHD, with the driver (engineer) sitting on the right, and the fireman (conductor) sitting on the left. This was customary in the UK and it spread to the USA and elsewhere in the world. RHD was never converted to LHD even if the trains switched to right-hand running. RHD remains the customary way for operating trains, with the driver on the right and assistant, sitting on the left side of the cab. Ironically, some railways, particularly, the London Underground, switched to LHD with left-hand running. Left Hand Drive with left hand running also became common on UK mainline railways, with the Great Western Railway being the only of the "big four" to keep the driver on the right. To ease visibility, GWR signals were also occasionally placed on the right-hand side of the tracks, even though this meant that they were between the running lines, and a few examples of this have managed to survive. Nowadays all British trains (except a few preserved locomotives and a number of narrow-gauge railways) have the driver on the left side of the train, and the signals are also on the left-hand side of the track.
In countries with trains keeping to the right it is often said that RHD is safer, as it is possible that something from a train passing on the left track (like opened cargo doors) may hit the train. In such case driver on the right is safer than if he were sitting to the left. Also, since signs and signals are usually placed on the outside of double track formations (e.g left hand side for left hand running or right hand side for right hand running), having the driver on the side as well makes it easier for them to see signs and signals, and also to view back along the platform either directly or using mirrors, particularly useful with one person operated trains. Finally, if 'train orders' or 'tokens' (permission to continue beyond a station or other control point) are handed-up or grabbed by the engine driver while rolling past, being on the 'outside' is mandatory to receive these 'orders/tokens'... Unlike on the road, it is possible for trains to safely run on the wrong side so long as bi-directional signalling is installed. This is normally only done in limited circumstances, since junctions and other infrastructure is usually optimised for running in one direction.
The driver is usually positioned near the centre of the vehicle, although some single-operator trams have been developed wherein the driver sits nearer the centre of the road. On the left-hand running Blackpool system and Melbourne trams built between the 1970s and 1990s, the driver sits on the right; on the old right-hand drive Zagreb trams, the driver sits on the left.
When Sweden changed to driving on the right, its single-ended trams were found to have the doors on the wrong side, and this was taken as an excuse to scrap the trams.
However, there are many exceptions, often indicated on the particular bridge itself.
The rule of the road at sea is that powered vessels give way to sailing vessels; but as between two powered vessels, if they are crossing the rule is to give way to the starboard, while if they are head on each must navigate to starboard so as to pass "port to port". See International Regulations for Preventing Collisions at Sea.
As well as the side of the road, priority rules also differ between countries. In the United Kingdom, priority is always indicated by signs or road markings, in that almost every junction not governed by traffic lights or a roundabout has a concept of a major road and minor road. In most of Continental Europe, the default priority is to give way to the right, but this default may be overridden by signs on major roads. In Germany, traffic on roundabouts used to have priority, but that rule was abandoned to align with other European countries. Now most roundabouts have give-way signs for traffic entering the roundabout. One special case is the Place de l'Étoile in Paris (the location of the Arc de Triomphe). Traffic on this particular roundabout is so chaotic that French insurance companies deem any accident on the roundabout to be equal liability. British and Irish drivers who are accustomed to having right of way by default unless they are specifically told to give way, are often more confused by the default give-way-to-the-right rule used on minor roads in nearby Continental Europe than they are by switching sides of the road.
When driving on the left:
When driving on the right:
Note: Italics indicates year of change to driving on the right.
Bosnia and Herzegovina
British Indian Ocean Territory
Cape Verde (1928)
Central African Republic
China, mainland (1946)
Czech Republic (1939, details)
Northern Mariana Is.
Republic of Macedonia
Saint Pierre and Miquelon
São Tomé and Príncipe (1928)
Sierra Leone (1971)
Slovakia (1939-41, details)
Spain (October 1924)
Sweden (1967, details)
United Arab Emirates
United States (1792)
Wallis and Futuna
Note: Italics indicates year of change to driving on the left.
Antigua and Barbuda
Cocos (Keeling) Islands
East Timor (drove on right 1928-1976)
Hong Kong, China - unlike mainland China
Isle of Man
Japan ''(Okinawa 1978)
Macau, China - unlike mainland China
Papua New Guinea
Pitcairn Islands |
Saint Kitts and Nevis
Saint Vincent and the Grenadines
Trinidad and Tobago
Turks and Caicos Islands
British Virgin Islands
U.S. Virgin Islands - unlike rest of U.S.
Poland's Galicia switched to the right around 1924. Czechoslovakia planned to start driving on the right on May 1, 1939, but the change in Bohemia and Moravia was prompted by the German occupation forces (Bohemia: March 26, 1939). Hungary also acted later than planned: the government decided about the change in June 1939 but postponed it and finally introduced it at 3am on 6 July 1941 outside Budapest and at 3am on 9 November 1941 in Budapest.
Some RHD vehicles can be found, particularly smaller Canada Post service trucks. These have extra mirrors to increase driver visibility. A few other vehicles, such as some garbage trucks or street cleaners may have dual LHD and RHD. The advantage of such arrangements is that the driver can hop in and out of the vehicle easily, and more easily observe their actions at the kerbside.
RHD vehicles are allowed for import in Canada, providing that they were manufactured over 15 years ago. For instance, before Rolls-Royces were marketed in Canada, the only imports available were RHD. Recently, however, Rolls-Royce and other expensive British automakers now manufacture LHD versions and have a Canadian office. Some Japanese RHD cars can be found as well, like the Nissan Skyline, Mitsubishi Delica and Mitsubishi Pajero. These cars are mainly found in British Columbia due to the proximity to Asian ports, but may also be found in cities such as Calgary, Toronto and Saskatoon.
One of the very few places in Canada where traffic drives on the left is in Montreal on Autoroute 20 for the between its junctions with Route 138 and Autoroute 15. The two roadways remain separated by a concrete median barrier for this entire distance and the changing of sides does not interfere in any way with the flow of traffic.
After 1946, China followed the United States, by changing to driving on the right, possibly due to political reasons that the United States helped China to fight against Japanese occupation during World War II and American cars (mostly LHD) were already popular in the mainland. This rule was also used in Taiwan after the Republic of China took over Taiwan from the Empire of Japan after World War II.
During the Cultural Revolution (1966-1976), Red Guards in some cities considered that to drive on the right side of road was to take the "rightist's route/policy", and they were said to have ordered vehicles to drive on the left side. Some also attempted to reverse the traditional meaning of traffic signals by having the red light mean "go" and the green light "stop". These two changes caused a great deal of confusion and resistance so both were abolished within several months.
However, in the south west of Guyana near Lethem, work is under way to build the Takutu River Bridge across the Takutu River into neighbouring Brazil, which drives on the right. Unlike road bridges between other countries that drive on opposite sides of the road, the changeover system will be in the country that drives on the left, i.e. Guyana, where one lane will pass under the other on the bridge's access road. Despite stalling construction in recent years, Brazil is keen to open the bridge, as it will give Brazil access to Caribbean sea ports on the north coast of South America. Brazil intends to permit Guyana registered (RHD) vehicles to go no further than the Brazilian border town of Bonfim. It is expected that Brazilian (LHD) vehicles will be able to drive all the way through Guyana to the coast. The bridge is expected to be completed by the middle of 2007. Once opened, the Takutu Bridge will be the Americas' only border crossing where traffic changes sides of the road.
In Suriname most of the privately owned buses are imported from Japan, and the exits are designed for driving on the left. Most state-owned buses, however, are from the US (LHD) and often the placement of the exits has to be adjusted.
Under the auspices of the one country, two systems arrangement, traffic continues to move on the left in Hong Kong and Macau, now Special Administrative Regions of the People's Republic of China, unlike in the mainland. Most vehicles are RHD and even suppliers for the People's Liberation Army have specially made RHD version vehicles for the garrison to drive in Hong Kong and Macau. LHD exceptions include some buses providing services to and from the mainland.
There are three road border crossing points between mainland China and Hong Kong. The largest and busiest is Lok Ma Chau (aerial map), which features two separate changeover systems on the mainland side. In 2006, the daily average number of vehicle trips recorded at Lok Ma Chau was 31100. The next largest is Man Kam To, where there is no changeover system and the border roads on the mainland side simply intersect as one-way streets with a main road. There are two border crossing points between mainland China and Macau. The newer crossing point is the Lotus Bridge, which crosses a narrow channel of sea between the mainland and Macau, and was opened at the end of 1999 (aerial map). The Lotus Bridge was designed to cater for high traffic volumes and features three lanes in each direction as well as a full changeover system on the mainland side, comprising bridges that loop around each other by 360° to swap the direction of the traffic. At the older Macau crossing point, there is no changeover system and the border roads continue with traffic on the left on the mainland side, and simply intersect on to a roundabout. All of these Chinese changeover systems can be viewed in high resolution using Google Earth.
After the defeat of Japan during World War II, Okinawa was under control of the United States and made to drive on the right. Okinawa was returned to Japanese control in 1972 and changed back to driving on the left six years later, at 06:00 on 30 July 1978. It is one of very few places to have changed from right to left hand traffic in the late twentieth century.
In Japan, foreign cars sold locally have traditionally been LHD, which is regarded as exotic or a status symbol. This even applies to British brands (although cars for the British market have the steering wheel on the right), in part because many have been imported via the U.S., but many other European countries have made RHD models for the Japanese market. Many tollbooths in Japan have a special lane for LHD vehicles. However, some U.S. manufacturers have made RHD models for the Japanese market (e.g., the Jeep Cherokee (XJ), Ford Probe, Ford Taurus, Saturn S-Series and Chevrolet Cavalier), albeit with limited success.
On the underground access road to the Manapouri power station vehicles must drive on the right. There are various theories about why this is so. It may be to make it easier for drivers to see how close they are to the tunnel wall, or it may be because the tunnel was built by European workers who drove on the right. The road is, however, only used by authorized vehicles and is not open to the public.
Although Russia drives on the right, cheaper used cars from Japan are almost as popular as LHD cars of the same class. Russia is estimated to have more than 1.5 million RHD vehicles on its roads. In the far eastern regions, such as Vladivostok or Khabarovsk, RHD vehicles make up to 90% of the total. This includes not only private cars, but also police cars, ambulances, and many other municipal and governmental vehicles.
During spring 2005, the rumour that RHD vehicles would be completely banned from the roads drove thousands of protesters to the streets everywhere in the country. On 19 May 2005 the Russian Minister of Industry and Energy Viktor Khristenko announced that RHD vehicles would be allowed on the roads but would have to conform to all Russian traffic safety requirements. Many automobile owners blocked the roads (in Moscow, Saint Petersburg, Vladivostok and many other cities), protesting against such an interdiction. On 19 May 2005 two automobile movements were born defending the interests of RHD automobile owners.
The purpose of adopting left-hand traffic is to allow Samoans to use cheaper RHD vehicles sourced from Australia and New Zealand, and so that the large number of Samoans living in these two countries can drive on the side of the road that they're familiar with when they visit home. When the change goes ahead, Samoa will become the first territory to change the side of the road for driving in 30 years. Prime Minister Tuilaepa Aiono Sailele Malielegaoi has come under criticism from Samoa's private sector, who argue that the amendment will harm small to medium size enterprises whose main business falls into the vehicle industry.
Sweden had left-hand traffic (Vänstertrafik in Swedish) from approximately 1734, when it changed back from a short period of right-hand traffic starting in 1718. Finland, under Swedish rule until 1809, also drove on the left, and continued to do so as a Russian Grand Duchy until 1858.
This continued well into the 20th century, despite the fact that virtually all the cars on the road in Sweden were LHD. (One argument for this was that it was necessary to keep an eye on the edge of the road, something that was important on the narrow roads in use at the time). Also, Sweden's neighbours, Norway and Finland already drove on the right, leading to confusion at border crossings.
In 1955 a referendum was held on the issue, resulting in an 82.9%-to-15.5% vote against a change to driving on the right. Nevertheless, in 1963 the Swedish parliament passed legislation ordering the switch to right-hand traffic. The changeover took place at 5am on Sunday, September 3, 1967, which was known in Swedish as Dagen H (H-Day), the 'H' being for Högertrafik or right-hand traffic.
Since Swedish cars were LHD, experts had suggested that changing to driving on the right would be safer, because drivers would have a better view of the road ahead. Indeed, fatal car-to-car and car-to-pedestrian accidents dropped sharply as a result, mostly because people initially drove more slowly and more carefully. However, the accident rate rose back to its original position within two years.
The U.K has left-hand traffic. Many countries owe the fact that they drive on the left to British colonial influence.
As a result of European Union legislation ensuring the free movement of goods, many British consumers exercise their right to buy RHD cars from car dealers in any other EU country, where they are often cheaper, despite originating from the same factories as UK-sourced cars. Models obtained from other EU countries often have a lower value upon resale due to shorter warranty periods and dealers protecting local interests.
Although the United Kingdom is separated from Continental Europe by the English Channel, the level of cross-Channel traffic is very high; the Channel Tunnel alone carries 3.5 million vehicles per year between the UK and France. Most vehicles crossing the English Channel, whether via the Channel Tunnel or on ferries, are UK-registered RHD vehicles. Relatively few drivers from Continental Europe take their LHD cars to the UK, but large numbers of British drivers take their RHD cars to Continental Europe for holidays and even for one-day shopping trips. It was reported in 2000 that Eurotunnel wished to build a second Channel Tunnel because the existing rail services are expected to outgrow their capacity by 2025. Unlike the existing rail tunnels, a drive-through road tunnel was planned, comprising a single bore tunnel containing one carriageway on top of the other. The current status of this project is unclear.
During the Lockerbie bomb trial of 2000-02, Camp Zeist in the Netherlands was decreed to be British territory subject to Scottish law. However, Dumfries and Galloway Police, who were responsible for policing traffic movements within the compound, effected a clause which required drivers to comply with the Continental European practice of driving on the right.
Vehicles within United States visiting forces bases in the United Kingdom drive on the left, even though the United States does not provide right-hand drive vehicles for its green fleet. However, its white fleet does have right-hand drive vehicles. This is unlike British practice in Germany, where even UK green fleet vehicles for British Forces Germany have been left-hand drive.
The first keep-right law in the United States, passed in 1792, applied to the Philadelphia and Lancaster Turnpike, between Lancaster and Philadelphia. New York (in 1804) and New Jersey (in 1813) also enacted keep-right rules.
Early American motor vehicles were produced in RHD, following the practice established by horse-drawn buggies. This changed in the early years of the 20th century: Ford changed to LHD production in 1908, and Cadillac in 1916.
Today, U.S. motor vehicles are normally LHD. Common exceptions include postal delivery vehicles, garbage trucks, and parking enforcement vehicles. Imported RHD cars are also found on the road in the United States, mostly classics or other collectors' items. American motorists nearly always drive on the right and overtake (pass) on the left, but are sometimes permitted to undertake (pass on the right) on multi-lane highways, one-way streets, or when passing other vehicles preparing to turn left. The laws vary from state to state.
The only entire U.S. territory with left-hand traffic is the United States Virgin Islands, to remain compatible with the nearby British Virgin Islands, though a large portion of the El Monte Busway in Los Angeles, California has eastbound traffic driving on the left side of the road. Some divided highways in the US that have small sections of road where the directions cross, resulting in traffic driving on the left; examples include the Golden State Freeway (I-5) in Southern California during the descent/ascent of the Castaic Grade, a very brief section of Interstate 275 in St. Petersburg, Florida (map), the I-8 Freeway east of Yuma, AZ (map), and state route 87 in Maricopa County, Arizona through Rincon Pass (map). Traffic at Phoenix's Sky Harbor airport also drives on the left around most of terminal 2 (map).