Drawing Lanes

Lanes are the fundamental building block of an Apollo HD map. Every other element (junctions, signals, overlaps, the routing graph) is defined in relation to lanes.

Draw a lane

1. Click Draw Lane in the toolbar (or press L)
2. Click on the map to place the first centerline point
3. Continue clicking to add intermediate vertices
4. Double-click the last point to finish the lane

The lane's left and right boundary lines appear immediately, offset from the centerline by width / 2 meters using turf.lineOffset.

Lane anatomy

         left boundary
    ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─

    ─────────────────────────────   ← center line (drawn / stored)

    ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─
         right boundary

The centerline is the only geometry stored in the editor. Boundaries are derived at render time and at export time.

Edit a lane

1. Click Select (or press S) and click the lane centerline
2. Drag any vertex to reposition it
3. Click a segment to add a new vertex (mapbox-gl-draw direct_select mode)
4. Press Delete / Backspace to remove the selected lane

Lane properties

With a lane selected, the Properties panel shows:

Property	Unit	Default	Apollo field
Width	meters	3.75	left_sample / right_sample (derived)
Speed limit	km/h (displayed), m/s (stored)	50 km/h	speed_limit
Lane type	enum	CITY_DRIVING	type
Turn	enum	NO_TURN	turn
Direction	enum	FORWARD	direction
Left boundary type	enum	DOTTED_WHITE	left_boundary.boundary_type
Right boundary type	enum	DOTTED_WHITE	right_boundary.boundary_type

Lane type values

Value	Apollo enum	Typical use
City Driving	CITY_DRIVING	Standard road lane
Biking	BIKING	Bike lane
Sidewalk	SIDEWALK	Pedestrian path
Parking	PARKING	On-street parking
Shoulder	SHOULDER	Road shoulder
Shared	SHARED	Shared pedestrian/bike

Boundary type values

Value	Rendering	Lane change allowed
DOTTED_WHITE	dashed white	Yes
DOTTED_YELLOW	dashed yellow	Yes
SOLID_WHITE	solid white	No
SOLID_YELLOW	solid yellow	No
DOUBLE_YELLOW	double solid yellow	No
CURB	solid thick	No
UNKNOWN	default	—

Routing implication

The routing map generator only creates lane-change edges between lanes whose shared boundary is DOTTED_WHITE or DOTTED_YELLOW. Set boundaries correctly or lane changes will not be available in the routing graph.

Boundary rendering styles

Each boundary type renders as a distinct MapLibre line style:

• Dotted boundaries → dashed line (line-dasharray: [4, 4])
• Solid boundaries → solid line
• Double yellow → two parallel lines rendered via offset layers
• Curb → thick solid line (line-width: 3)

Lane fill color is keyed to lane type:

Lane type	Fill color
CITY_DRIVING	blue-gray
BIKING	green
SIDEWALK	orange
PARKING	purple
SHOULDER	brown

Direction arrows

A chevron arrow is drawn at the midpoint of each lane centerline, pointing in the lane's heading direction. This makes it easy to verify FORWARD vs BACKWARD direction visually.