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.

View current restriction relations in the database - Restriction Analyser

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 is 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 (possible 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 do not start/end at the "via"-node, split it!
2. Avoid using ways as the "via" member unless you absolutely have to - not all routing implementations will support ways as "via" members. You are on the safe side if your "via" member is a node.

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 ore more	the nodes or ways 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

	Road Sign	Restriction	Remark
1	a File:No left turn a.png / b File:No left turn b.png	restriction=no_left_turn	a) germany, italy b) france, spain, poland, ireland, uk
2	a File:No right turn a.png / b File:No right turn b.png	restriction=no_right_turn	a) germany, italy / b) france, spain, poland, ireland, uk
3	a File:No straight on a.png / b	restriction=no_straight_on	a) germany, poland / b) ireland (uk never uses such signs - you would be facing a No Entry sign in such a situation)
4	a / b	restriction=no_u_turn	a) germany, france, spain, poland / b) united kingdom
5	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
6	a File:Only left turn a.png / b File:Only left turn b.png	restriction=only_left_turn	-
7	File:Only straight on a.png	restriction=only_straight_on	-

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.

Examples

Map	Tag and Members	Descriptions
	restriction=only_right_turn way A role from way B role to node n role via	At n from A only turning right to B is allowed. So turning to left is forbidden.
	restriction=no_left_turn way A role from way B role to node n role via	Turning left form A to B is not allowed at n. But going straight and right is not forbidden. The other 3 restrictions at this crossing have to be defined all separate.

See Also

• JOSM_Relations_and_Turn_Based_Restrictions