A three-way junction (or three-way intersection) is a type of road intersection with three arms. A Y junction (or Y intersection) generally has three arms of equal size coming at an acute or obtuse angle to each other; while a T junction (or T intersection) also has three arms, but one of the arms is generally a smaller road joining a larger road at right angle.
Some three-way junctions are controlled by traffic lights, while others rely upon drivers to obey right-of-way rules, which vary from place to place:
In the United States and some other countries, it is common to have stop signs facing each direction, although according to game-theoretical analysis, drivers have strong incentives to run the stop sign, while randomly removing one stop sign may lead to significant efficiency gains. [4]
In the People's Republic of China, going straight on red when approaching a T junction on the main road with the intersecting road on the left was permitted until the Road Traffic Safety Law of the People's Republic of China took effect on 1 May 2004.
When one road at a 3-way junction has a higher traffic volume than the other (and particularly when the roads are perpendicular to each other), turns are characterized as "right-in", "right-out", "left-in" and "left-out". A turn "in" represents a turn from the major road into the minor road. A turn "out" represents a turn out of the minor road onto the major road. A 3-way junction allowing all four of these turns is characterized as "full-movement". These terms also apply to turns between roads and driveways. [5] [6]
An experiment was done[ by whom? ][ when? ] in Illinois, United States to allow going straight on red (like a right turn on red) when approaching a T junction on the main road, with the intersecting road on the left. It was a failure. However, at some T junctions where the main road includes at least two lanes on the side away from the intersecting road, the farthest (rightmost, in areas where traffic drives to the right) lane is given the right of way to proceed straight through the intersection at all times, denoted by a "green arrow" signal if a traffic light is installed at the intersection.
In such cases, often that lane is also specially delimited with pavement markings or other lane separation devices, to keep left-turning traffic on the intersecting road from colliding with traffic proceeding through the intersection on the main road. There are now safer variations of this, called continuous green-T (or seagull) intersections , that have a left turn lane off the main road either channelized or otherwise separated from traffic going straight, which allows for a traffic signal on only one side of the road. [7]
In Thailand, three-way junction was called in an old word Sam Phraeng (Thai : สามแพร่ง, pronounced [sǎːmpʰrɛ̂ŋ] ). Sam Phraeng is unsuitable area according to the beliefs of Thai people since ancient times on account of it is a passageway of ghosts or demons, therefore, normally no one will build a house or residence in the Sam Phraeng area. This belief also appears in China, Japan, and Korea. [8]
Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads/sidewalks) for travel and transportation.
A roundabout, a rotary and a traffic circle are types of circular intersection or junction in which road traffic is permitted to flow in one direction around a central island, and priority is typically given to traffic already in the junction.
An intersection or an at-grade junction is a junction where two or more roads converge, diverge, meet or cross at the same height, as opposed to an interchange, which uses bridges or tunnels to separate different roads. Major intersections are often delineated by gores and may be classified by road segments, traffic controls and lane design.
Traffic lights, traffic signals, or stoplights – also known as robots in South Africa and Namibia – are signaling devices positioned at road intersections, pedestrian crossings, and other locations in order to control the flow of traffic.
Priority traffic signs indicate the order in which vehicles shall pass intersection points. Vehicles often come into conflict with other vehicles and pedestrians because their intended courses of travel intersect, and thus interfere with each other's routes. The general principle that establishes who has the right to go first is called "right of way" or "priority". It establishes who has the right to use the conflicting part of the road and who has to wait until the other does so. The vehicle that does not need to wait is said to "have the right of way" or to "have priority."
A jughandle is a type of ramp or slip road that changes the way traffic turns left at an at-grade intersection. Instead of a standard left turn being made from the left lane, left-turning traffic uses a ramp on the right side of the road. In a standard forward jughandle or near-side jughandle, the ramp leaves before the intersection, and left-turning traffic turns left off of it rather than the through road; right turns are also made using the jughandle. In a reverse jughandle or far-side jughandle, the ramp leaves after the intersection, and left-turning traffic loops around to the right and merges with the crossroad before the intersection.
A hook turn or two-stage turn, also known as a Copenhagen Left, is a road cycling manoeuvre or a motor vehicle traffic-control mechanism in which vehicles that would normally turn from the innermost lane of an intersection instead turn from the outermost lane, across all other lanes of traffic.
Turn on red is a principle of law permitting vehicles at a traffic light showing a red signal to turn into the direction of traffic nearer to them when the way is clear, without having to wait for a green signal.
In traffic engineering, there are regional and national variations in traffic light operation. This may be in the standard traffic light sequence or by the use of special signals.
Priority to the right is a right-of-way system in right-hand traffic, in which the driver of a vehicle is required to give way to vehicles approaching from the right at intersections. The system is stipulated in Article 18.4.a of the Vienna Convention on Road Traffic for countries where traffic keeps to the right and applies to all situations where it is not overridden by priority signs, including side roads and roundabouts.
Road signs in Iceland are visual communication devices placed along roads and highways throughout the country to provide information, warnings, and guidance to motorists and pedestrians. Iceland never ratified the Vienna Convention on Road Signs and Signals, but road signs in Iceland conform to the general pattern of those used in most other European countries, with certain design elements borrowed from Danish and Swedish practice. Signs tend to be more sparsely employed than in other European countries, especially in rural areas.
An all-way stop – also known as a four-way stop – is a traffic management system which requires vehicles on all the approaches to a road intersection to stop at the intersection before proceeding through it. Designed for use at low traffic-volume locations, the arrangement is common in the United States, Canada, Mexico, South Africa, and Liberia, as well as in a number of, usually rural, locations in Australia where visibility on the junction approaches is particularly poor. The stop signs at such intersections may be supplemented with additional plates stating the number of approaches.
A seagull intersection or continuous green T-intersection is a type of three-way road intersection, usually used on high traffic volume roads and dual carriageways. This form of intersection is popular in Australia and New Zealand, and sometimes used in the United States and other countries.
Road signs in Thailand are standardized road signs similar to those used in other nations but much of it resembles road signage systems used in South American countries with certain differences, such as using a blue circle instead of a red-bordered white circle to indicate mandatory actions. Until the early 1980s, Thailand closely followed American, European, Australian, and Japanese practices in road sign design, with diamond-shaped warning signs and circular restrictive signs to regulate traffic. The Department of Railway maintains a standard on the typeface used in the sign, with custom made type for Thai text, unofficially named "Thang Luang" (อักษรทางหลวง) and a small derivation of FHWA Series fonts typeface, which is used on American road signage, for Latin text. In most Bangkok Metropolitan Area's routes, TS Lopburi is still used.
The design of road signs in Poland is regulated by Regulation of the Ministers of Infrastructure and Interior Affairs and Administration on road signs and signals. The Annex 1 to the regulation describes conditions related to usage of the road signs – size, visibility, colors and light reflections, typeface and text, criteria of choosing the type of foil to signs faces, colorful specimens and schematics.
Road signs in New Zealand are similar to those set by the Vienna Convention on Road Signs and Signals. While New Zealand is not a signatory to the convention, its road signs are generally close in shape and function. New Zealand uses yellow diamond-shaped signs for warnings in common with Australia, the Americas, Ireland, Japan and Thailand. Speed limit signs are a red circle with a white background and the limitation in black, and are in kilometres per hour. There are also some signs unique to New Zealand. Road signs in New Zealand are controlled by NZ Transport Agency Waka Kotahi and are prescribed in the Land Transport Rule: Traffic Control Devices 2004 and set out in the Traffic Control Devices (TCD) Manual.
A protected intersection or protected junction, also known as a Dutch-style junction, is a type of at-grade road junction in which cyclists and pedestrians are separated from cars. The primary aim of junction protection is to help pedestrians and cyclists be and feel safer at road junctions.
Terminology related to road transport—the transport of passengers or goods on paved routes between places—is diverse, with variation between dialects of English. There may also be regional differences within a single country, and some terms differ based on the side of the road traffic drives on. This glossary is an alphabetical listing of road transport terms.
Bosnia and Herzegovina is a signatory to the Vienna Convention on Road Signs and Signals. Therefore, road signs do not differ much from the rest of Europe, such as Croatia, Slovenia, Serbia and North Macedonia. Ministry of Transportation of Bosnia and Herzegovina regulates them. Bosnia and Herzegovina drives on the right as with the rest of Europe, except for Cyprus, Ireland, Malta and the United Kingdom. Bosnian and Herzegovinan road signs have two scripts, Latin and Cyrillic script.
Road signs in Cambodia are standardized road signs are similar to those used in Europe but much of it resembles road signage systems used in South American countries with certain differences. The designs of road signage match their neighbours of Thailand and Malaysia, both of which adopt a modified version of the South American road signage system. Until the early 1980s, Cambodia closely followed American, European, Australian, and Japanese practices in road sign design, with diamond-shaped warning signs and circular restrictive signs to regulate traffic. Unlike Thailand and Malaysia, Cambodia does not use the FHWA Series fonts typeface, favouring Helvetica instead.
