Relation:restriction

This is a proposal for a set of tags and members making a Relation to represent a turn restriction at a junction or other restrictions (you don't have to be turning - you may not be allowed to go straight on - e.g. a bus gate is a kind of junction where the restriction is no passage from one side to the other - except for buses of course).

There may be several turn restrictions at a junction, represented by separate relations.

There is no need to model no turning into the wrong way of a one way street - we take this for granted.

Tags

Key	Value	Explanation
type	restriction
restriction	no_right_turn / no_left_turn / no_u_turn / no_straight_on / only_right_turn / only_left_turn / only_straight_on	If the first word is "no", then no routing is possible from the "from" to the "to" member, and if it is "only_", then you know that the only routing originating from the "from" member leads to the "to" member. The "from" and "to" members must start/end at the "via" node (see 1).
except	psv / bicycle / hgv / motorcar	The restriction does not apply to these vehicle types (more than one: except=bicycle;psv)
day_on	day of week	for example, no right turn in the morning peak on weekdays might be day_on=Monday;day_off=Friday;hour_on=07:30;hour_off=09:30
day_off	day of week
hour_on	time of day
hour_off	time of day

1. If the way does not start or end at the "via"-node, split it!

Members

Way or Node	Role	Recurrence?	Discussion
	from	one	a way from which restriction starts (e.g. no right turn from here)
	to	one	the other end of the restriction
	via	one (node) / one or more (way)	the nodes or way between the end points across which you would travel if the turn weren't restricted - may just be the simple intersection of the two ways, or consider a dual carriageway where you can't turn across it, where via would be the nodes on each carriageway and/or the little way connecting the two carriageways.
	location_hint	optionally one	a hint to a renderer as to where might be a good place to position a symbol indicating the restriction. e.g. in a N/S/E/W cross roads where you can't turn from S to E, you might put a node just SE of the junction and the renderer might place a no right turn sign there.

Road signs

The sign number in the US MUTCD is given in parentheses. There are slight differences of these roadsigns from country to country. Images of turn-signs all around the world can be found on Wikimedia Commons

	Road Sign	Restriction	Remark
1	File:No left turn a.png	restriction=no_left_turn + restriction=no_u_turn	Germany, Italy, Japan, The Netherlands, Russia
2	File:No left turn b.png	restriction=no_left_turn	Australia, Brazil, France, Ireland, Poland, Russia, Spain, Switzerland, UK, US (R3-2; R3-18 combined with no U-turn)
3	a File:No right turn a.png b File:No right turn b.png	restriction=no_right_turn	a) Germany, Italy, Japan, The Netherlands, Russia b) Australia, Brazil, France, Ireland, Spain, Poland, Russia, Switzerland, UK, US (R3-1)
4	a File:No straight on a.png b	restriction=no_straight_on	a) Germany, Japan, The Netherlands, Poland, Russia, Switzerland b) Brazil, Ireland (US, UK and France never use such signs - you would usually be facing a No Entry sign in such a situation, or if it's two-way ahead you might see adjacent left-turn-only and right-turn-only signs)
5	a b	restriction=no_u_turn	a) Germany, France, Japan, Spain, Poland, Switzerland, Brazil, The Netherlands, US (R3-4) b) Australia, Russia, United Kingdom
6	a File:Only right turn a.png b File:Only right turn b.png	restriction=only_right_turn	(a) typically approaching the junction and (b) at the junction In the US, a white rectangular sign is used for this situation and the case where one lane on a multi-lane road must turn (R3-5R)
7	a File:Only left turn a.png b File:Only left turn b.png	restriction=only_left_turn	(a) typically approaching the junction and (b) at the junction In the US, a white rectangular sign is used for this situation and the case where one lane on a multi-lane road must turn (R3-5L)
8	File:Only straight on a.png	restriction=only_straight_on	Used in Russia and in the United Kingdom; usually seen just before a junction or on the approach to a junction In the US you'll see the text "NO TURNS" in a white square (R3-3; R3-5a is usually used only in the case where one lane on a multi-lane road must turn)

Obviously, the above table can't be complete, e.g. swedish road signs use a yellow background instead of the white one. However, with the above signs it should be easy to find the corresponding restriction=xy value for most countries.

In Brazil, all signs in this category, whether no_turn or only_turn is a red circular sign with an arrow pointing in the direction. only_turn signs does not have the diagonal bar, while no_turn signs have (similar to 1-3b, but also for 5-7).

Examples

Map	Tag and Members	Descriptions
	type=restriction restriction=only_right_turn way A has role 'from' way B has role 'to' node n has role 'via'	At n from A only turning right to B is allowed. So turning to left is forbidden.
	type=restriction restriction=no_left_turn way A has role 'from' way B has role 'to' node n has role 'via'	Turning left form A to B is not allowed at n. But going straight and right is not forbidden. Each of the other 3 restrictions at this crossing have to be defined separate.
	type=restriction restriction=no_right_turn way A has role 'from' way B has role 'via' way C has role 'to'	Users coming from way A cannot exit through way C.

Editors

• Download the turnrestrictions plugin to create and edit turn restrictions in JOSM
• See also how to edit turn restrictions in JOSM
• Potlatch 2 has a built-in turn restriction editor
• Junction Editor in Mapzen. It is in Beta version now, if you want to try it - send a request to mapzen@cloudmade.com

Errors

• Bugs from skobbler user

See also

• Jughandle
• Different tagging (not ways but nodes for from and to) used at enforcement

Tools

• OSM Restriction Analyser - shows route restrictions as an overlay of sign-post icons. zoomed example (Be patient, XAPI is often overloaded.)
• cartography.sandbox.cloudmade.com/navdebug - Another map overlaying sign post icons
• Relation Check - Tool to generate a graphical display of relations, including restrictions, from a local .osm file.