page_title: Left- and right-hand traffic
section_title: Changing sides at borders
hierarchical_section_title: Left- and right-hand traffic / Changing sides at borders
context_page_description: Left-hand traffic and right-hand traffic are the practices, in bidirectional traffic, of keeping to the left side or to the right side of the road, respectively. They are fundamental to traffic flow, and are sometimes referred to as the rule of the road.
  RHT is used in 165 countries and territories, with the remaining 75 countries and territories using LHT. Countries that use LHT account for about a sixth of the world's land area, with about a third of its population and a quarter of its roads. In 1919, 104 of the world's territories were LHT and an equal number were RHT. Between 1919 and 1986, 34 of the LHT territories switched to RHT.
  Many LHT countries were formerly part of the British Empire, although many were not, such as Sweden, Japan, Thailand, Indonesia, Nepal and Suriname, among others. Conversely, many RHT countries were part of the French colonial empire.
  In LHT traffic keeps left, and cars have the steering wheel on the right, putting the driver on the side closest to the centre of the road. Roundabouts circulate clockwise. RHT is the opposite of this: traffic keeps right, the driver sits on the left side of the car, and roundabouts circulate anticlockwise.
context_section_description: Although many LHT jurisdictions are on islands, there are cases where vehicles may be driven from LHT across a border into a RHT area. Such borders are mostly located in Africa and southern Asia. The Vienna Convention on Road Traffic regulates the use of foreign registered vehicles in the 78 countries that have ratified it.
  LHT Thailand has three RHT neighbours: Cambodia, Laos, and Myanmar. Most of its borders use a simple traffic light to do the switch, but there are also interchanges which enable the switch while keeping up a continuous flow of traffic.
  There are four road border crossing points between Hong Kong and Mainland China. In 2006, the daily average number of vehicle trips recorded at Lok Ma Chau was 31,100. The next largest is Man Kam To, where there is no changeover system and the border roads on the mainland side Wenjindu intersect as one-way streets with a main road.
  The Takutu River Bridge (which links LHT Guyana and RHT Brazil) is the only border in the Americas where traffic changes sides.
  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 by the Eurotunnel Shuttle between the UK and France.
caption: Traffic Switchover sign at the Thai–Lao Friendship Bridge