Relation:type=route_instruction
Proposal status:	Abandoned (inactive)
Proposed by:	pov
Tagging:	`type=route_instruction`
Statistics:
Rendered as:	hidden
Draft started:	2009-01-21
RFC start:	2009-01-24

The proposal is to provide guiding instructions at intersections besides what can be deduced from the topology itself.

Rationale

Topology itself is not sufficient to provide satisfactory driving instructions.

For instance, topology wise, those two intersections are identical, but instructions should be different.

Discussion showed that using the lane number is sufficient to make the difference in this case.


english	take the next exit to the right	stay on the right lane
german	Ausfahrt rechts nehmen	Auf der rechten Spur bleiben
french	prenez la prochaine sortie à droite	serrez à droite

This example also clearly shows that instructions must be stored in a language agnostic format.

Remember that not on all countries all exits go to the same direction.

Here's another more complex example. Where topology is not sufficient.

you can see it [here], it's the junction from A 15 to both A 86 going east and west and N 135.

Destination	Instructions based on topology	Instructions corresponding to real life
A	turn slightly right, then turn slightly right	stay on the rightmost lane
B	turn slightly right, then turn slightly left	stay on the two middle lanes
C	turn slightly left	stay on the leftmost lane

Applies to

Multiple ways.

Key	Required	Value	Discussion
type	required	route_instruction
to_n_instruction	required	possible values : `straight_ahead` “straight ahead” `right_turn` “turn right” `left_turn` “turn left” `exit` “take the next exit” `right_exit` “take the next exit at right” `left_exit` “take the next exit at left” `right_lane` “stay right” `middle_lane` “stay in the middle” `left_lane` “stay left” `follow_main_road` ”stay on the main road” `none` no instruction, it's obvious to follow that direction without instructions The lane values can be suffixed by a colon and a number if more than one lane are grouped, like this `left_lane:2` which means in English “the two leftmost lane”, if no value is specified no value should be assumed and more generic instruction should be used like “stay left”, “stay in the middle”	n is an integer which is the number assigned to the member way in the relation
to_n_directional_sign	optional	free text value used to reproduce the signs shown on the street to aid guiding
to_n_phonetic_direction	optional	This is an help to pronunciation of the directions (for tts software) and must be expressed in either [IPA] or [X-SAMPA] as declared in the `to_n_phonetic_direction_format`
to_n_phonetic_direction_format	optional	Defines which format was used to represent the phonetic direction. Can be either `IPA` or `X-SAMPA`, with IPA being the default value if this tag is not used.

Way or Node	Role	Quantity	Discussion
	`from`	one	the way that is about to be left
	`to_n`	one or more	the ways that are about to be entered. These ways are not required to have any common nodes with the from node, there could be a another way in between. n is an integer, ways should be numbered in ascending order starting from one for clarity

Tags

Members

Tags

Members

Note here that there's no instruction for way C, this is not a mistake.

Tags

Members