Tag:junction=circular

The junction=circular tag is used for circular road intersections where traffic on the junction does not have complete right of way (as opposed to a junction=roundabout). It includes traffic circles (also called rotaries) along with other circular (self-intersecting) road junctions. It can include intersection controls such as traffic signals, stop signs or markings, give way (or yield) signs or markings. They can vary from small to very large with several lanes.

The rotary or circular junction should not have any road network inside itself. Thus, ring roads around a city are not valid circular junctions.

How to map

Draw a circular shape which would represent the junction. It may be a single closed way, or a chain of multiple connected ways forming a ring. Each way should be tagged with an appropriate highway=* value and the junction=circular.

Generally, rotaries and circular junctions have one-way traffic and should have the tag oneway=yes; however, circular junctions with bi-directional traffic do exist, and should be tagged with oneway=no.

Furthermore:

• The OSM ways of the junction must be drawn in the direction the traffic flow.
• Connect it with the roads approaching the circular junction. If a road is split into two separated carriageways (one approaching, one departing), draw those explicitly and tag these carriageways with oneway=yes. Pay attention to their correct orientation and use separate nodes of the circular junction for the approaching and departing road.
• Also, tag the junction and approaches with highway=*, the same as the connecting roads. If there are several roads of different importance connecting to the junction, usually use the one with the greatest importance, that does not begin or end at the junction. More details about selecting the correct tag can be found on the junction=roundabout page.
  • Generally, each incoming road has to be connected with the circular junction in a separate node—that is, between these nodes a segment of the circular junction is required. Thus routers can safely recognise that a section of the circular junction has to be driven through.
  • It is suggested to map traffic lights, signs and road markings using highway=traffic_signal, highway=give_way and highway=stop.
• A roundabout should only be tagged with name=* if the junction itself is named independently and differently from the roads crossing it. Within cities, a circular junction may be the backbone of a named square and carry its name.

Misclassification

Please pay attention to the section Possible misinterpretations to differentiate between:

• Roundabouts (junction=roundabout)—where traffic on the roundabout has right of way;
• Rotaries and traffic-circles (junction=circular)—where traffic on the rotary or circular junction does not have right of way;
• Mini roundabouts (highway=mini_roundabout)—used only on nodes, as a roundabout where the centre of the roundabout must be traversable;
• Turning circles (highway=turning_circle)—used only on nodes, including cul-de-sacs; and
• Turning loops (highway=turning_loop)—used only on nodes, where a road island or similar feature is present.

Distinguishing from roundabouts

Berlin, Strausberger Platz

Berlin, Großer Stern

• If one of the roads entering the circle has the right-of-way and the other has to yield (Example: Berlin, Strausberger Platz)
• If the circular traffic in the junction always has to yield to incoming traffic (Example: Berlin, Großer Stern)
• If a (section of) the junction allows bi-directional traffic

This form of a junction allows the major and minor road to intersect in one node only, typically in an acute angle. An example is the Strausberger Platz in Berlin, Germany.

Purpose

The tag allows routing software to recognise circular junction structures more easily for cases that fail the OSM roundabout definition. OSRM has implemented the tag. There is no impact to expect on visual map rendering.

Implications for routing

Routing software will usually call out both the entrance to and exit from a circular junction, but it should avoid doing so when the junction is small enough. For example, OSRM treats a circular junction with a diameter less than 15 metres (49 ft) as a plain intersection[1][2].

See also

• highway=* - The highway tag is the primary tag used for any kind of street or way
• junction=roundabout - A road junction where the traffic goes around a non-traversable island and has right of way
• highway=mini_roundabout - A road junction where the traffic goes around a painted circle or traversable island and has right of way

Related terms: ‹ roundabout › ‹ traffic circle › ‹ rotary › ‹ road circle › ‹ rotunda ›