Definition
Functional Requirements
Syntax
Semantics
Conformance Testing
Performance Assessment
1 Definition
Road Attributes is a Data Type describing the structural, regulatory, and usage‑related characteristics of a Road Segment as required by the Autonomous Motion Subsystem (AMS) for Motion Planning, Risk Assessment, and Trajectory Feasibility analysis.
2 Functional Requirements
The Road Attributes include, at minimum, the following:
- NumberOfLanes – the count of physically designated lanes.
- Length – linear extent of the road segment.
- Width – nominal road or lane width.
- MaxSpeed – maximum regulated speed.
- MinSpeed – minimum regulated speed when applicable.
- MaxHeight – maximum clearance allowed.
- MaxWeight – maximum permitted vehicle gross weight.
- LaneUsage – direction of travel allowed (e.g., forward, backward).
- Category – functional classification (e.g., oneway, toll, link).
- Types – structural road type (e.g., highway, street, avenue, boulevard, lane).
The AMS may use Road Attributes for Road State integration, route feasibility assessment, safe trajectory generation, and for verifying regulatory constraints such as lane direction, speed limits, and vehicle admissibility based on height or weight.
3 Syntax
https://schemas.mpai.community/CAV2/V1.1/data/RoadAttributes.json
4 Semantics
| Header | Road Attributes Header – Standard “CAV‑RDA‑Vx.y”. |
| MInstanceID | Identifier of the M-Instance (Virtual Space) associated with this Road Attributes instance. |
| UEnvironmentID | Identifier of the U-Environment (Real Space) associated with this Road Attributes instance. |
| RoadAttributesID | Unique identifier of this Road Attributes instance. |
| RoadAttributesTime | Time this Road Attributes instance was produced. |
| RoadAttributesSpaceTime | Space/Time where/when this Road Attributes instance applies. |
| NumberOfLanes | Number of physically designated lanes on the road segment. |
| Length | Linear extent of the road segment (metres). |
| Width | Nominal road or lane width (metres). |
| MaxSpeed | Maximum regulated speed on the road segment (km/h). |
| MinSpeed | Minimum regulated speed on the road segment, when applicable (km/h). |
| MaxHeight | Maximum allowable vehicle clearance height (metres). |
| MaxWeight | Maximum permitted vehicle gross weight (kg). |
| LaneUsage | Direction of travel permitted: one of “forward”, “backward”. |
| Category | Functional classification of the road segment: one of “oneway”, “toll”, “link”. |
| Types | Structural road type: one of “highway”, “street”, “avenue”, “boulevard”, “lane”. |
| DataXMData | MPAI-PTF Data Exchange Metadata providing provenance, authorisation, legal, security, and confidence information associated with this Road Attributes instance in a trusted data exchange context. |
| DescrMetadata | Human-readable descriptive metadata of the Road Attributes instance (plain text, max 2048 characters). |
5 Conformance Testing
A Data instance conforms with Road Attributes (CAV‑RDA) if:
- The Data validates against the Road Attributes’ JSON Schema.
- All Data in the Road Attributes’ JSON Schema:
- Have the specified type.
- Validate against their JSON Schemas.
- Conform with their Data Qualifiers.
6 Performance Assessment
Not part of this specification.
