NDD Vehicle ClassVehicle Class

Overview

A vehicle class describes how a group of vehicles interacts with each dimension in the model. This includes linking vehicles to transit generators for distance and time matrices, and specifying coefficients that scale transit, task, and location quantities. Multiple vehicles may share the same vehicle class.

Applicable models

• NDD ndd-cmibu6krtqja

VehicleClass

Schema definition

message VehicleClass {
  required string id = 1;
  repeated Attribute attributes = 2;
  repeated string transitRuleIds = 3;
}

Fields

id

A unique identifier for this vehicle class.

attributes

A list of vehicle class attributes defining how this class interacts with each dimension.

transitRuleIds

A list of transit rule identifiers that apply to all vehicles in this class.

Examples

id: "standard-class"
attributes {
  dimensionId: "time"
  transitGeneratorId: "road-time"
  transitCoef: 1.0
  taskCoef: 1.0
  locationCoef: 1.0
}
attributes {
  dimensionId: "distance"
  transitGeneratorId: "road-distance"
  transitCoef: 1.0
}

Vehicle Class Attribute

A vehicle class attribute defines how a particular dimension is evaluated for vehicles in this class.

Schema definition

message Attribute {
  required string dimensionId = 1;
  optional string transitGeneratorId = 2;
  optional float transitCoef = 3;
  optional float taskCoef = 4;
  optional float locationCoef = 5;
}

Fields

dimensionId

The dimension to which this attribute applies.

transitGeneratorId

The identifier of a transit generator which provides the base transit values (e.g. road network times or distances) for this dimension.

transitCoef

A coefficient applied to the transit values. A value of 1.0 uses the transit values as-is. Values greater than 1.0 increase transit quantities (e.g. to model slower vehicles), and values less than 1.0 decrease them.

taskCoef

A coefficient applied to task-level quantities on this dimension.

locationCoef

A coefficient applied to location-level quantities on this dimension.

Notes

• A transitGeneratorId is typically specified for time and distance dimensions, linking the vehicle class to the road network via a transit generator.
• Coefficients allow the same transit generator to be shared across vehicle classes that travel at different speeds.