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Remove lanes
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brad-richardson committed Oct 2, 2024
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35 changes: 0 additions & 35 deletions counterexamples/transportation/segment/road/bad-road-invalid-min-occupancy-value.json
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39 changes: 0 additions & 39 deletions counterexamples/transportation/segment/road/bad-road-invalid-min-occupancy.json
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277 changes: 3 additions & 274 deletions docs/schema/concepts/by-theme/transportation/roads.mdx
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Expand Up @@ -14,9 +14,6 @@ import ExampleAccessRestrictionAxleLimit from '!!raw-loader!@site/docs/_examples
import ExampleSpeedLimitsSimple from '!!raw-loader!@site/docs/_examples/transportation/docusaurus/speed-limits-01-simple.yaml';
import ExampleSpeedLimitsDirectional from '!!raw-loader!@site/docs/_examples/transportation/docusaurus/speed-limits-02-directional.yaml';
import ExampleSpeedLimitsVariableMax from '!!raw-loader!@site/docs/_examples/transportation/docusaurus/speed-limits-03-variable-max.yaml';
import ExampleLanesResolutionConnector from '!!raw-loader!@site/docs/_examples/transportation/docusaurus/lanes-resolution-connector.yaml';
import ExampleLanesResolutionSegment01 from '!!raw-loader!@site/docs/_examples/transportation/docusaurus/lanes-resolution-segment-01.yaml';
import ExampleLanesResolutionSegment02 from '!!raw-loader!@site/docs/_examples/transportation/docusaurus/lanes-resolution-segment-02.yaml';
import ExampleTurnRestriction1Source from '!!raw-loader!@site/docs/_examples/transportation/docusaurus/turn-restriction-01-source.yaml';
import ExampleTurnRestriction1Target from '!!raw-loader!@site/docs/_examples/transportation/docusaurus/turn-restriction-01-target.yaml';
import ExampleTurnRestriction1Exit from '!!raw-loader!@site/docs/_examples/transportation/docusaurus/turn-restriction-01-exit.yaml';
Expand All @@ -39,10 +36,9 @@ in many cases, approximates the physical centerline of the section of
road being modeled. Road segments support modeling the road network at a range of
granularities. For example, a single road segment can represent:

- bidirectional street including all of its lanes and sidewalks
- bidirectional street including all of its sidewalks
- sidewalk by itself
- one-way street or one direction of a dual carriageway
- single lane or single section of a multi-lane highway
- dedicated cycleway
- hiking path

Expand Down Expand Up @@ -108,8 +104,7 @@ resolve.)

The implied access restrictions may be modified for the road segment as
a whole by providing an explicit value for the property
`access_restrictions`. (Access restrictions may also be specified
at the level of individual [lanes](#lanes), as explained elsewhere.)
`access_restrictions`.

It is technically possible to specify a blanket access grant or refusal
of access applying to everyone and everything; but where, as is typical,
Expand Down Expand Up @@ -328,9 +323,7 @@ limits.

The implied speed limits may be configured for the whole road segment by
providing an explicit value for the property
`speed_limits`. Note: granular speed limits can also be
specified at the level of individual [lanes](#lanes), as explained
elsewhere.
`speed_limits`.

As with access restrictions and turn restrictions, speed limits can be specified using [rules](/schema/concepts/scoping-rules#rules-and-rule-based-properties).

Expand All @@ -353,267 +346,3 @@ As with access restrictions and turn restrictions, speed limits can be specified

</TabItem>
</Tabs>

## Lanes

A road may optionally carry a `lanes` property which, if present, contains
a list of rules that can be used to resolve the applicable traffic lane block
for the road. A lane block is a list of lane objects. Each lane object in the
block describes the physical structure and properties applicable to one the
road's traffic lanes at a granularity sufficient to support the navigation use
case. Note that the `lanes` property applies to traffic lanes, not to
parking lanes.

### Use cases for lanes

Many transportation use cases can be solved either entirely or in large part without examining the lane
structure of the road network. For example, optimal route calculation
can be entirely solved without lane-level information, as can most 2D
map rendering problems. Lane information is most interesting for
granular turn-by-turn or maneuver-by-maneuver navigation applications.

### Default lane structure

If the `lanes` property is omitted from a road segment, reasonable
default values should be assumed based on `class` and the
road-level [access restrictions](#access-restrictions). For example, for
a stock two-way road segment of class `primary` with no heading-scoped
access restrictions, a reasonable assumption is two lanes, one
`forward` and one `backward`.

### Lane numbering

The number of lanes at a given place and time on a road segment is equal to
the length of the lanes list within the resolved lane block.

Each entry in the resolved lanes list represents one lane on the road.
Order is important. The list captures the lanes in left-to-right order
as they would be observed by a person standing on the physical road being modeled, facing in the [direction](/schema/concepts/by-theme/transportation/shape-connectivity#directionality)
of the segment geometry. The leftmost lane has index `0`; the rightmost
lane, assuming there are N total lanes, has index N-1. The example
below illustrates how lane numbering works with example two-lane
segments oriented in the north, west, east, and south directions,
respectively.

<figure>

<div style={{ display: "flex", alignItems: "center" }}>

<div style={{ width: "27%", float: "left", textAlign: "center" }}>

<ThemedImage
alt='West-oriented road segment with two lanes.'
sources={{
light: useBaseUrl('/img/transportation/lane-number-01-west-light.png'),
dark: useBaseUrl('/img/transportation/lane-number-01-west-dark.png'),
}}
/>

</div>

<div style={{ width: "10px", float: "left" }}/>

<div style={{ width: "23%", float: "left", textAlign: "center" }}>

<ThemedImage
alt='North-oriented road segment with two lanes.'
sources={{
light: useBaseUrl('/img/transportation/lane-number-02-north-light.png'),
dark: useBaseUrl('/img/transportation/lane-number-02-north-dark.png'),
}}
/>

</div>

<div style={{ width: "10px", float: "left" }}/>

<div style={{ width: "27%", float: "left", textAlign: "center" }}>

<ThemedImage
alt='East-oriented road segment with two lanes.'
sources={{
light: useBaseUrl('/img/transportation/lane-number-03-east-light.png'),
dark: useBaseUrl('/img/transportation/lane-number-03-east-dark.png'),
}}
/>

</div>

<div style={{ width: "10px", float: "left" }}/>

<div style={{ width: "23%", float: "left", textAlign: "center" }}>

<ThemedImage
alt='South-oriented road segment with two lanes.'
sources={{
light: useBaseUrl('/img/transportation/lane-number-04-south-light.png'),
dark: useBaseUrl('/img/transportation/lane-number-04-south-dark.png'),
}}
/>

</div>

<div style={{ clear: "both" }}/>

</div>


<figcaption>

<div style={{textAlign: 'center'}}>

*How lanes are numbered for examples segments with geometry directions due west, north, east, and south.*

</div>

</figcaption>

</figure>

### Lane directionality

Each lane within a segment has a directionality, documenting which
travel directions are allowed within the lane, with reference to the [orientation of the segment](/schema/concepts/by-theme/transportation/shape-connectivity#start-end-and-orientation). Lane directionality is specified by the lane object's `directionality`
property. The allowed values are:

<figure>

<div style={{width: '100%', display: 'flex', justifyContent: 'center'}}>

| Directionality | Meaning |
|-|-|
| `forward` | Travel is only allowed along the `forward` heading. |
| `backward` | Travel is only allowed along the `backward` heading. |
| `both_ways` | Travel is allowed both `forward` and `backward` at the same time. |
| `alternating` | Travel is one-way and changes between `forward` and `backward` constantly. |
| `reversible` | Travel is one-way and changes between `forward` and `backward` infrequently. |

</div>

<figcaption>

<div style={{textAlign: 'center'}}>

*Allowed values for lane `directionality`.*

</div>

</figcaption>
</figure>

The `directionality` property is a mandatory property for lanes, and is
the only mandatory property.

When the allowed travel heading changes based on a regular schedule,
the appropriate "definite" directionalities (`forward`, `backward`, and
`both_ways`) should be used along with [temporal scoping](/schema/concepts/scoping-rules#temporal-scoping-opening-hours) at the lane block level.

When the allowed travel heading changes based on unpredictable local
factors, such that allowed heading at any given time can only be known
by an observer actually present at the real-world location, the
appropriate indefinite directionality (`alternating` or `reversible`)
should be used.

### Lane restrictions

Like the segment a whole, each lane within a lane block can have its own
restrictions, for example [access restrictions](#access-restrictions),
[turn restrictions](#turn-restrictions) and
[speed limits](#speed-limits).

Lane-level restrictions reuse the same concepts as segment-level
restrictions and are typically phrased in the same way, except that the
restriction is stipulated on an individual lane object rather than for
the segment's `road` property as a whole.

### Lane connectivity

Lane connectivity refers to the maneuvers available to navigate from the
lane the traveller is currently occupying to a connected lane within the
next lane block in the traveller's current travel direction. Lane
connectivity is a necessary element for granular turn-by-turn
navigation instructions.

The Overture transportation schema does not currently support lane
connectivity, but it is something we are actively working on and hoping
to release soon.

### Resolving the applicable lane block

The traffic lane structure of a road segment can be different at different
points along the segment, or at different times of the day, or both.
Consequently, instead of having a static lane block, road segments carry a list of lane block [rules](/schema/concepts/scoping-rules#rules-and-rule-based-properties)
in the optional `lanes` property.

- A rule may be scoped [geometrically](/schema/concepts/scoping-rules#geometric-scoping-linear-referencing),
which allows linear referencing to be used to specify the portion of the
segment geometry where the lane block exists.
- A rule may also be scoped [temporally](/schema/concepts/scoping-rules#temporal-scoping-opening-hours), which allows the time of day that the lane block exists to be specified. Temporal scoping is useful for modeling cases like lanes which are used
for parking at off hours and traffic during peak hours. In such a case,
the lane block rule would be scoped to peak hours.

As with all rule-based properties in the Overture schema, the [rule evaluation algorithm](/schema/concepts/scoping-rules#rule-evaluation-algorithm) must be applied to determine which lane block rule, if any, is
applicable at a given place and time along the road segment. Once the
determining rule for a certain scope is known, its rule block defines
the lane structure within that scope.

The example below illustrates lane block resolution for two connected
segments.

- The blue shaded, or southwesterly, segment is [oriented](/schema/concepts/by-theme/transportation/shape-connectivity#directionality) toward the north-east. It has two geometrically-scoped lane block rules:
- The first rule, applying to the first two thirds of the
segment's length, establishes three lanes: one going
`backward` (SW), and two `forward` (NE).
- The second rule, applying to the last third of the segment,
establishes two lanes, one in either direction.
- The green shaded, or northeasterly, segment is oriented due west. It
has a single static lane block that applies to the whole segment
geometry at all times.

<Tabs>
<TabItem value="diagram" label="Diagram" default>

<div style={{ textAlign: "center" }}>

<figure>

<ThemedImage
alt='A segment with two geometrically-scoped lane blocks connected to a segment oriented in the opposite direction.'
sources={{
light: useBaseUrl('/img/transportation/lane-blocks-light.png'),
dark: useBaseUrl('/img/transportation/lane-blocks-dark.png'),
}}
/>

<figcaption>

*A segment with two [geometrically-scoped](/schema/concepts/scoping-rules#geometric-scoping-linear-referencing) lane blocks connected to a segment oriented in the opposite direction.*

</figcaption>

</figure>

</div>

</TabItem>

<TabItem value="segment1" label="Segment 1 Data">

<CodeBlock language="yaml">{ ExampleLanesResolutionSegment01 }</CodeBlock>

</TabItem>

<TabItem value="connector" label="Connector Data">

<CodeBlock language="yaml">{ ExampleLanesResolutionConnector }</CodeBlock>

</TabItem>


<TabItem value="segment2" label="Segment 2 Data">

<CodeBlock language="yaml">{ ExampleLanesResolutionSegment02 }</CodeBlock>

</TabItem>

</Tabs>
2 changes: 1 addition & 1 deletion docs/schema/concepts/by-theme/transportation/shape-connectivity.mdx
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Expand Up @@ -204,7 +204,7 @@ back toward the start of the segment.
-->
🚧 We are developing a segment-level directionality concept similar to [lane directionality](/schema/concepts/by-theme/transportation/roads#lane-directionality) to indicate what travel headings are allowed or prohibited along the segment. This effort is
🚧 We are developing a segment-level directionality concept to indicate what travel headings are allowed or prohibited along the segment. This effort is
ongoing, so please check back soon.
### Sub-types
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