Three-way junction

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Three way junction at Dragons Green - - 1578998 Three way junction at Dragons Green - - 1578998.jpg
Three way junction at Dragons Green - - 1578998

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. A T junction (or T intersection) also has three arms, but one of the arms is generally a minor road connecting to a larger road.



Some T junctions are controlled by traffic lights, but others rely upon drivers to obey right-of-way rules, which vary from place to place. For example, in some jurisdictions, vehicles on the right always have the right-of-way (even at T junctions), [1] while in other jurisdictions, vehicles travelling on the "through" road of a T junction have the right-of-way, meaning that vehicles approaching the "major" road must allow through traffic to pass before joining the flow of traffic.

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.

In Taiwan (administered by the Republic of China), when at least two vehicles reach a T intersection without a working traffic light, the vehicle on the side road is to yield to any other vehicle straight on the main road. If two vehicles want to turn left, the vehicle on the left is to yield. [2]


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. [3] [4]


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. [5]

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Roundabout Traffic intersection

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Traffic light signalling device to control competing flows of traffic

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Diamond interchange common type of road junction

A diamond interchange is a common type of road junction, used where a freeway crosses a minor road.


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 it rather than the through road. Right turns are also made using the jughandle.

Superstreet Type of high capacity intersection

A superstreet, also known as a restricted crossing U-turn (RCUT), J-turn, or reduced conflict intersection, is a type of road intersection that is a variation of the Michigan left. In this configuration, in contrast to the Michigan left, traffic on the minor road is not permitted to proceed straight across the major road or highway. Drivers on the minor road wishing to turn left or go straight must turn right onto the major road, then, a short distance away, queue (wait) into a designated U-turn lane in the median. When traffic clears, they complete the U-turn and then either go straight or make a right turn when they intersect the other half of the minor road.

Interchange (road) road junction, typically using grade separation

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Road signs in Iceland

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Road signs in Thailand

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The road signs in Poland follow the Vienna Convention on Road Signs and Signals and, therefore, are more or less identical to those in other European countries. Warning signs have yellow background rather than the more common black-on-white design, and therefore similar to the Road signs in Greece.

Road signs in Israel

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These road signs are used in Germany.

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Road signs in Cambodia

Road signs in Cambodia are standardized road signs similar to those used in other nations but with certain differences. Until the early 1980s, Cambodia closely followed US, Australian, and Japanese practices in road sign design, with diamond-shaped warning signs and circular restrictive signs to regulate traffic. Cambodia traffic signs use Khmer, the national language of Cambodia, however, English is also used for stop and important public places such as tourist attractions, airports, railway stations, and immigration checkpoints. Both Khmer and English are used on directional signage. Cambodia signed the Vienna Convention on Road Signs and Signals but have yet to ratify the convention.

These road signs are used in Vietnam.

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  1. SGI. "SGI - Driver's Handbook - Right of way".
  2. Clause 2 of Section 1 of Article 102 of the Road Traffic Security Rules (s:zh:道路交通安全規則)
  3. Staff. "Technical Summary (FHWA-SA-10-002)". Access Management in the Vicinity of Intersections. Federal Highway Administration . Retrieved August 31, 2012.
  4. Joe G. Bared (January–February 2005). "Improving Signalized Intersections, Publication Number: FHWA-HRT-05-003". Public Roads. Federal Highway Administration. 68 (4). Retrieved August 31, 2012.
  5. An Applied Technology and Traffic Analysis Program ( "Archived copy". Archived from the original on 2012-02-08. Retrieved 2007-10-12.CS1 maint: archived copy as title (link))