What each network contains

Each mode is its own schema with its own edges, nodes and edge_graph. Monaco:

Mode	Edges	Nodes	Speed
driving	2,765	1,719	the speed limit, or a default per road class
walking	10,952	4,116	5 km/h
cycling	10,274	4,151	15 km/h; 5 km/h on dismount edges

Which OSM ways each mode keeps

Mode	Keeps
driving	highway = motorway, trunk, primary, secondary, tertiary (and their _links), unclassified, residential, service, living_street, road. Also highway=pedestrian when motorcar or motor_vehicle is yes / designated / permissive, or access is delivery / destination: these become living_street
walking	every way people may walk on: highway = footway, path, pedestrian, steps, living_street, residential, service, platform, corridor, track, bridleway, road, unclassified, tertiary, secondary, primary, trunk (and their _links). Not a road tagged motorroad=yes, foot=use_sidepath, or sidewalk (or sidewalk:both, or both sidewalk:left and sidewalk:right) = separate: people walk on its separately mapped sidewalk. Any way tagged foot = yes / designated / permissive or sidewalk = yes / both / left / right is kept. Never motorway or motorway_link. Walking
cycling	highway = cycleway, path, track, bridleway, living_street, residential, service, unclassified, tertiary, secondary, primary (and their _links); any way tagged bicycle = yes / designated / permissive, or with a cycleway tag other than no / none / separate. Plus dismount edges

Then the access tags decide, per mode.

Every mode needs a highway tag: a way with only foot, bicycle or sidewalk tags, or with only area:highway (the outline of a pedestrian area), is not a road and is in no network. The one exception is the ferry line (route=ferry, with foot=yes for walking or bicycle=yes for cycling): in Monaco it comes into walking, where it is walked at 5 km/h like a footpath, and its highway is ferry (its walk_type is footpath, its cycle_type mixed_traffic).

highway=service (driveways, parking aisles, alleys) is part of the network like any other road.

Access: private and forbidden roads

For each mode, the most specific access tag decides:

Mode	Tags, most specific first
driving	motorcar, motor_vehicle, vehicle, access
walking	foot, access
cycling	bicycle, vehicle, access; on a dismount edge: foot, access

Its value	The road in that mode
no (driving also agricultural, forestry, emergency)	not there. It stays in the other modes that may use it: a road tagged motor_vehicle=no is still walkable
private	visible, never routable: in <mode>.private_edges, not in edges
driving only: for buses only (below)	visible, never routable, like a private road: in driving.private_edges with access = 'bus'
anything else (yes, destination, delivery, …) or none	a normal road

So access=private + motor_vehicle=yes is a normal road for driving, and motor_vehicle=no doesn't affect walking or cycling. The mode's value is kept in edges.access.

Private roads (a driveway, a gated street, a company road) are built like every other road, with the same edge_id formula, then moved from edges to private_edges, which has the same columns except the H3 ones. The component filter doesn't prune private_edges. So routing, the graph of legal turns and every export use only roads you may use, and a road you can reach only through a private one is dropped with the component filter. The maps still draw private roads, marked (Draw a map).

Bus lanes and bus-only roads are cars' private roads too: in driving they are built, then moved to private_edges with access = 'bus'. A bus-only road is one with highway=busway, or whose driving access is psv, or no / private while bus or psv is yes / designated (psv means buses and taxis; both count as bus). A bus lane against a one-way street (oneway=yes with oneway:bus=no or oneway:psv=no) adds the reverse edge, as a bus lane: its edge_id is the same as that direction in cycling and walking. Monaco: 18 bus edges, among them the contraflow bus lane of Boulevard des Moulins.

Pedestrian streets in driving

A highway=pedestrian way that cars may use (motorcar or motor_vehicle is yes, designated or permissive, or access is delivery, destination or agricultural) is a living_street in driving.edges. Every other pedestrian way is built in driving too (cut at the same points, with the same edge_id as in walking), then moved to driving.private_edges with highway = 'pedestrian'. access tells why cars cannot use it:

The most specific car tag (motorcar, motor_vehicle, vehicle, access)	access
delivery (from motorcar or motor_vehicle)	delivery
private	private
none, no, or any other value	pedestrian

These ways are never routed or exported. The maps draw them. Other path classes (footway, path, steps, cycleway) are not in driving. Norrmalm: 831 edges (783 pedestrian, 32 delivery, 16 private); driving.edges is unchanged. Design: docs/design/pedestrian_private_edges.md.

Monaco:

Mode	Routable edges	In private_edges
driving	2,765	689 (473 pedestrian, 198 private, 18 for buses)
walking	10,952	154
cycling	10,274	133

A way a mode leaves out is still in raw.ways, with all its tags. To remove or keep one road yourself, use a fix.

One-way roads

A one-way edge has no reverse twin, so the road can only be used from source to target.

Mode	One-way when
driving	oneway = yes / 1 / true / -1; junction = roundabout / circular; motorway and motorway_link unless oneway=no
cycling	as driving (without the motorway rule), but oneway:bicycle=no makes it two-way and oneway:bicycle=yes one-way. Dismount edges are always two-way
walking	only oneway:foot = yes / 1 / true / -1

oneway=-1 (one-way against the way's drawing direction) is turned round, so its edge runs the legal way.

Speeds and travel time

maxspeed_kmh is never empty. For driving it is the maxspeed tag when it is a number, converted when it ends in mph, and otherwise (untagged, or a value like RU:urban or walk) a default:

Road class	km/h
motorway, motorway_link	110
trunk, trunk_link	90
primary, primary_link	70
secondary, secondary_link	60
tertiary, tertiary_link	50
unclassified, road	40
residential	30
living_street, service	20
any other class	50

Monaco: 899 of the 2,765 driving edges have a maxspeed tag.

cost_s, the travel time in seconds, is length_m / (maxspeed_kmh / 3.6). It uses the speed limit: no traffic, no delay at junctions. Routing and the edge graph use it.

Lanes

lanes is the number of lanes in the edge's own direction, never empty, except on connector edges (walking, cycling), where it is NULL:

1. lanes:forward / lanes:backward, when tagged.
2. A one-way road: all of lanes.
3. A two-way road: lanes split in two, at least 1 each way; the drawing direction gets the larger half.
4. Nothing tagged: 2 for motorway and trunk, otherwise 1.

A lanes:reversible lane is added to both directions. Monaco: 1,165 of the 2,765 driving edges are on a way with a lanes tag.

Dismount edges

Cycling also gets footways and pedestrian streets, so that cycleways joined only by them stay connected. On those where riding isn't allowed (bicycle isn't yes / designated / permissive), dismount is TRUE: the bike is pushed, at 5 km/h, in both directions, and cycle_type is dismount. Their access is the walking one (foot, then access): no leaves them out, private moves them to private_edges. A connector edge that extends a dismount path is dismount too. Monaco: 7,240 of the 10,274 cycling edges. For a ride-only network, use WHERE NOT dismount; options.cycling_dismount: false leaves them out of the build.

walk_type and cycle_type

Walking and cycling edges get a type from OSM sub-tags. The first rule that matches wins.

walk_type	From
escalator / steps	highway=steps, with / without conveying
sidewalk / crossing / footpath	highway=footway with footway=sidewalk / footway=crossing / anything else
plaza / pedestrian_street	highway=pedestrian, with / without area=yes
shared_street	living_street
sidewalk	any other road with a sidewalk tag (not no / none / separate): you walk its sidewalk
shared_road	residential, service, unclassified, road, tertiary, secondary, primary, trunk (and their _links): walked on the carriageway
corridor	highway=corridor, or indoor=yes
platform	highway=platform
path	path, track, bridleway
footpath	anything else

cycle_type	From
dismount	a dismount edge
cycleway	highway=cycleway
cycle_track / cycle_lane / shared_lane / bus_cycle_lane	the cycleway tag on the edge's side: track / lane / shared_lane / share_busway
segregated_path / shared_path	path, track, bridleway, with / without segregated=yes
mixed_traffic	anything else, including a footway or pedestrian street you may ride (bicycle=yes)

The side is cycleway:right for an edge in the drawing direction and cycleway:left for its reverse, then cycleway:both, then cycleway.

Turn restrictions

Only the driving network has them. They come from OSM relations type=restriction with a from way, a via node and a to way, and from the turn rules of a fixes file. A no_* restriction removes that one turn from edge_graph; an only_* restriction removes every other turn from the from edge. Monaco: 38 of the 43 restriction relations map onto edges.

Not used: restrictions through a via way, the except tag, and tags like restriction:hgv or restriction:conditional. Any turn not removed is allowed, including a U-turn onto the reverse twin of a two-way road.

Bus routes

Buses have no network of their own: the OSM bus route relations (route = bus, trolleybus, share_taxi) are matched to the driving edges they travel, and stored in schema bus (bus.routes, bus.route_edges). A build from a PBF with driving does it (options.bus_routes, on); duckosm bus DB adds it to a file built before.

A route relation lists its ways in travel order; its stops and platforms are left out. Each way is travelled from the node it shares with the way before to the node it shares with the way after, so its direction comes from its neighbours, and on a two-way street that picks the #nf or the #nr edge. The first or last way of a stretch, where only one neighbour is known, is travelled from or to its far end; when it is joined in its middle (or is a stretch alone), the role forward / backward decides, else the way's one-way. A roundabout is followed from where the route enters to where it leaves. The edges come from driving.edges and, for bus lanes and bus-only roads, driving.private_edges with access = 'bus': a bus against a one-way street runs on its contraflow bus lane.

Nothing is left out silently. bus.routes.outside counts the member ways outside the area; bus.routes.gaps lists every other way the route could not be followed on, as '<way_id> <kind>':

Kind	The way
no_connection	shares no node with the next member way: the route breaks there
no_edge	has no driving edge (nor bus lane) in the direction travelled
private	is a private road (in driving.private_edges, not for buses)
role_conflict	has a role (forward / backward) its neighbours contradict; the neighbours are followed
ambiguous	the first or last way of a stretch, two-way, joined in its middle, no role: its direction can't be told
role	has a role other than '', forward, backward

Monaco: 56 bus routes, none with gaps (38 run partly outside the area), 5,609 route edges on 1,034 driving edges, 14 of them bus lanes. The contraflow bus lane of Boulevard Charles III (1449981121#1r) carries lines 3, 607 and X1.

The level area marks these edges: bus is in their modes and bus_lines lists the lines, e.g. 1, 2, 5.