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

Tags

Key	Value	Discussion
type	restriction
restriction	no_right_turn / no_left_turn / no_u_turn / no_straight_on	so that a renderer could place an appropriate icon/sign, or a route planner verbalise the restriction
except	psv / bicycle / hgv / car	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_on	day of week
hour_on	time of day
hour_off	time of day
(and other similar ones from Map_Features)

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 or more	the nodes and 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.