Proposal:Circuit

A racing venue may be composed of more than one circuit, and it will be useful to identify these. Motor racing tracks seem to be generally tagged highway=raceway, leaving reference to the name=* tag to figure out which part you're looking at. For instance, the main track at Donington Park has two circuits

Advantages

Anyone that needs to produce a map of a specific circuit (such as Image:Silverstone_Circuit2.png) need only look up the relation to establish which ways need to be rendered. Unlike relying on highway=* alone, this would also work on street circuits such as in Monte Carlo.

Tags

Key	Value	Discussion
type	circuit
name	a name

Members

Way or Node	Role	Recurrence?	Discussion
	forward/backward	one or more	No longer used. Was used to indicate direction - as for members of relation type=route, no longer used there, provided that way members are correctly ordered (their drawing direction may be changed; in some cases the circuit will use it backward, notably for oneway highways (for vehicles) that may be used backward for a non-permanent pedestrian, cycle or motorway racing circuit: in that case it is still preferable to indicate this case with the backward role to disambiguate it). Some circuits will use the same way multiple times but in opposite directions, here again the role helps disambiguate the circuit, as the ordering of ways in the relation may be altered and no longer strictly ordered when splitting ways in editors. Only the default role "forward" (circuit using the way in the same direction as the drawing direction of the way itself) no longer needs to be indicated (and not needed if the way is effectively oneway).
	pit_lane	optionally one	a venue may have more than one access, or even more than one pit lane - this identifies the path used with the specific circuit
	start	optionally one	the start used for this circuit. Note that if the circuit forms a loop (starts and ends at the same point), the first way and last way of the relation must be correctly ordered and contain that node.