Slice.md

Slice Specification

Field name	Nested Fields	Level in JSON Hierarchy	Type	Required	Description
geometry		1	JSON LineString	Required	SharedStreets geometry compliant LineString that is in WGS Coordinates. The orientation of right vs. left is based the the order of the vertices in this geometry, and its start and end points denote the crosswalk locations described in the specification.
sharedstreetid		1	ID	Required	SharedStreets ID for the specific segment of a consolidated centerline (no dual carriageways). This should be a unique ID. This field will be located in the properties of the GEOJSON.
slices		1	JSON	Required	Denotes from left to right, slices of a right of way, whose subattributes denote its characteristics.The main sub-attribute are the type of slices (drive_lane, bike_lane,walkway, etc), its width in meters, its height in meters, its direction (forward or reverse), and a meta-data tag with other information about the slice (color, improvement year, or other information). These JSON slices will be located in the properties of the GEOJSON.
	type	2	String	Required	Denotes the type of slice being referenced. Meta data tags may be associated with each type to give supplementary information about the type. Type information should correspond to the additive specification, but also provide flexibility for new or emerging lane types. Possible slice types are documented in the Slice Types Table.
	width	2	Float	Required	Denotes the width in meters of the slice.
	height	2	Float	Required	Denotes the height in centimeters (cm) of the slice relative to the rest of the road. Defaults to 0.
	direction	2	String	Required	Denotes whether the slice is facing forward (towards the geometry end point) or reverse (towards the geometry start point).
	material	2	String	Required	A string value indicating the paving material of the surface, e.g. "asphalt", "concrete", "cobblestone", "dirt", etc. (There should be some attempt at standardizing common values but allow custom values to be used.) This should not be a required value because specific slices can assume default values, e.g. the default value of paving for a drive_lane, if not specified, is "asphalt". Allow "none" if slice is not paved; e.g. plants, water
	meta	2	JSON	Optional	This denotes any other metadata to be associated with the slice. This will likely be a work in progress. Relevant meta tags are documented in the Slice Types Table.

Slice Types

Slice Type	Meta Tags	Sub-Meta Tags	Type	Required	Description
(all)					Meta tags permitted on all slices
	material		String	No	A string value indicating the paving material of the surface; e.g. "asphalt"; "concrete"; "cobblestone"; "dirt"; etc. (There should be some attempt at standardizing common values but allow custom values to be used.) This should not be a required value because specific slices can assume default values; e.g. the default value of paving for a drive_lane; if not specified; is "asphalt". Allow "none" if slice is not paved; e.g. plants; water
	color		String	No	A string value indicating painted color for the slice (e.g. "red" is common for bus lanes; "green" or "blue" for bike lanes). Allow some other descriptive words for special patterns or artwork
	height		Number	No	The height of the surface in centimeters relative to the road surface. While the geometry can encode Z coordinates for absolute elevation; this attribute specifically for knowing the vertical height of surfaces relative to the street. A typical curb can be 4 to 6 inches in height (10.2 - 15.2 cm); while just the asphalt road bed would be considered be at height 0.
	transitions		JSON	No	Definition in flux; but these transition properties describe how the edge of one slice should transition to a neighboring slice based on some criteria. E.g. a drive_lane next to another_drive lane might have a transition of a broken white line. A raised curb next to an asphalt-paved slice might have a gutter; or a ramp; or other types of transitions.
		end	JSON	No	This denotes how end point transitions are defined in the specification. They are in the form: {index_position_of_connecting_street_slice: transition_type}. The index position indicates where the connecting slice is on the other street; and the transition type can have the values of : angled; s-shaped; offset; and semi-circle.
		start	JSON	No	This denotes how start point transitions are defined in the specification. They are in the form: {index_position_of_connecting_street_slice: transition_type}. The index position indicates where the connecting slice is on the other street; and the transition type can have the values of : angled; s-shaped; offset; and semi-circle.
AUTOMOTIVE (DEDICATED)					"Dedicated" means "primarily intended for." In each of these cases mixed traffic may be permitted and a meta tag will indicate what kind of mixing is allowed.
drive_lane			String	Yes	This denotes a through-lane intended for automobile traffic.
	sharrow		Boolean	Optional	Describes whether a drive_lane slice has a sharrow stamp located within it.
turn_lane					A lane where automobiles are taken out of traffic flow in order to queue for turning. These lanes are considered to be center-running and can be bidirectional if they represent a block to block segment with end and begin depths for symmetrical intersection end points (no additional turn lanes on either end of the segment). Segments should be split if one block has varying turn lanes counts.
	sharrow		Boolean	Optional	A turn_lane may have a sharrow stamp
	end_depth		Number	Conditionally Required	This specifies the turn lane depth for the end point of the existing segment. If blank, it is assumed the turn lane is the depth of the entire length of the represented segment. For block to block representations, this parameter is required, and only works for symmetrical end points of intersections.
	begin_depth		Number	Conditionally Required	This specifies the turn lane depth for the start point of the existing segment. If blank, it is assumed the turn lane is the depth of the entire length of the represented segment. For block to block representations, this parameter is required, and only works for symmetrical end points of intersections.
	end_movements_allowed		String	Conditionally Required	This specifies the movements allowed at the turn. They are represented by a "
	begin_movements_allowed		String	Conditionally Required	This specifies the movements allowed at the turn. They are represented by a "
	remainder_allocation		String	Conditionally Required	This specifies the allocation that remains in between turn lane pockets. If blank, it is assumed to be a median. Otherwise, it can take on the properties of a slice type outlined in the specification. For block to block segments, this parameter is required unless the turn lanes takes up the full length of the segment.
	direction		String	Optional	This specifies the direction of the non-turnlane element after a transition ends. If none, assumed to be bidirectional.
NON-AUTOMOTIVE (DEDICATED)
sidewalk					Through-lane dedicated to pedestrians; usually (but not always) on a raised curb
	accessible		Boolean		Sidewalk meets accessibility regulations (e.g. ADA in the US)
bike_lane					Through-lane dedicated to bicycles or other vehicles of similar shape and speed.
bus_lane					Through-lane dedicated to busses.
	brt		Boolean	Optional	Whether the bus lane is dedicated to bus rapid transit as opposed to regular buses.
	bikes_allowed		Boolean	Optional	Whether the bus lane allows bikes (may have a sharrow stamp)
	taxi_allowed		Boolean	Optional	Whether the bus lane allows taxis (or other shared mobility)
transit					A through-lane with fixed infrastructure (e.g. rail-based transit)
	type		String	Required	A string value indicating the type of rail transit (trolley;light rail;heavy rail)
	autos_allowed		Boolean	Optional	Whether the transit lane permits automobiles.
	bus_allowed		Boolean	Optional	Whether the transit lane permits non-fixed-rail transit; e.g. buses
	bikes_allowed		Boolean	Optional	Whether the bus lane allows bikes (may have a sharrow stamp)
	taxi_allowed		Boolean	Optional	Whether the bus lane allows taxis (or other shared mobility)
path					A shared-use path intended for both bicycle and pedestrian traffic.
	bikes_allowed		Boolean	Optional	Whether the path allows bikes (may have a MUTCD bicycle stamp).
	pedestrians_allowed		Boolean	Optional	Whether the path allows pedestrians.
MIXED LANES
limitless					A specially designated through-lane intended for any non-automotive vehicle.
CURB ZONE					Curb zones are the liminal space between through traffic and a pedestrian zone which have usually been reserved for automobile parking; but more recently; segments of the curb zone have been chopped up and designated for other uses. Therefore curb zones may be portions of slices from point A to B. Note that there is a very fine line between some types of uses in a curb zone and miscellaneous objects.
flex_zone			String	No	Generic designation for a curb zone with varying uses.
parking			String	No	A lane dedicated for automobile parking.
parklet			String	No	A parking area converted to a pedestrian-use area.
commercial_loading			String	No	A loading zone; primarily for the loading and unloading of goods
passenger_loading			String	No	A loading zone; primarily for passenger pickup/drop-off.
transit_stop			String	No	A location that is reserved for public transit vehicle loading, unloading, and dwelling.
commercial_activity			String	No	A zone where commerce is permitted; e.g. food trucks; farmer's markets; newsstands
bike_parking			String	No	A zone where some designated of bicycle parking will be placed.
bike_share			String	No	A zone where a docked bicycle share installation will be placed.
dockless_parking			String	No	A zone where dockless bicycle shared or scooters can be parked.
construction_zone			String	No	A zone that indicates there is currently construction taking up space.
tow_away_zone			String	No	A zone where tow-away rules are in place at nearly all times.
MISCELLANEOUS
median				Yes	A raised street slice whose elements are in the center of the street.
	type				The type of median allowed. Possible values include: paint;curb; vegetated; vegetated_with_trees; stone; brick; other.
buffer				No	A raised street slice whose elements typically provide some degree of protection to a multimodal lane such as a bike lane.
	type				The type of buffer allowed. Possible values include: paint;post;curb;planter;separator;vegetated; vegetated_with_trees;vegetated_with_tree_curb_cuts; stone;bollard;brick; other.
temporary				No	Any slice that has been reconfigured for a temporary purpose; e.g. construction
	type				What is this temporary purpose (e.g. construction; event)
	barrier_type				If the slice is a barrier; type of barrier (e.g. traffic cone; jersey barrier; fencing; etc)
transit_shelter				No	An area / platform for waiting for transit
planting_strip				No	An area for plants; primarily for decorative purposes (though it can have an ecological impact). Usually placed in a sidewalk (as opposed to a median).
	type				The planting strip type describes the type of vegetated buffer provided. Possible values include:vegetated; vegetated_with_trees;vegetated_with_tree_curb_cuts
filter_strip				No	An area designated for stormwater management; which is usually (but not required to be) vegetated.
canal				No	A water channel