tnc request table structure

tnc request table structure#

The TNC_Request table stores records for all requests recevied by any shared mobility operator in POLARIS. A variety of information is recorded to understand demand for the different shared mobility services, and the outcome details when trying to serve the request is also logged.

The data in this table is purely an output of POLARIS and is not read back in by subsequent iterations.

Table Structure#

Field

Type

NULL allowed

Default Value

Foreign key

Description

TNC_request_id*

INTEGER

NO

Unique identifier for requests that are made in the simulation.

request_time

REAL

YES

0

Time at which the request was made (units: seconds)

reserve_time

REAL

YES

0

Time for which the request was made, either same as request_time or ahead (units: seconds)

assignment_time

REAL

YES

0

Time at which the request is assigned to a vehicle or 0 if not assigned. (units: seconds)

pickup_time

REAL

YES

0

Time at which the request was picked up by the vehicle or 0 if not assigned. (units: seconds)

dropoff_time

REAL

YES

0

Time at which the request was dropped off by the vehicle or 0 if not assigned or was not dropped off before simulation ended. (units: seconds)

access_walk_duration

REAL

YES

0.0

Time needed for request to walk to vehicle from origin before pickup, if needed. (units: seconds)

egress_walk_duration

REAL

YES

0.0

Time needed for request to walk to destination from vehicle after dropoff, if needed. (units: seconds)

origin_location

INTEGER

NO

0

Location of the request origin. Can be 0 if origin is not near any location and is only tagged by a link. (foreign key to the Location table)

destination_location

INTEGER

NO

0

Location of request destination. Can be 0 if destination is not near any location and is only tagged by a link. (foreign key to the Location table)

origin_link

INTEGER

NO

0

Link of the request origin. Cannot be NULL/0. (foreign key to the Link table)

destination_link

INTEGER

NO

0

Link of the request destination. Cannot be NULL/0. (foreign key to the Link table)

adjusted_origin_location

INTEGER

NO

0

Certain assignment strategies may alert requests to walk/move to a nearby location from the origin and the new origin Location ID is stored in this column.

adjusted_destination_location

INTEGER

NO

0

Certain assignment strategies may alert requests to walk/move from a nearby location to the destination and the new destination Location ID is stored in this column.

adjusted_origin_link

INTEGER

NO

0

Certain assignment strategies may alert requests to walk/move to a nearby link from the origin and the new origin Link ID is stored in this column.

adjusted_destination_link

INTEGER

NO

0

Certain assignment strategies may alert requests to walk/move from a nearby link to the destination and the new destination Link ID is stored in this column.

service_mode

INTEGER

NO

0

The shared mobility mode requested that is consistent with the entries in the Mode table. Options now include TNC, On-Demand Delivery, or Relocation for E-Scooters.

origin_zone

INTEGER

NO

0

The origin Zone of the request (foreign key to the Zone table)

destination_zone

INTEGER

NO

0

The destination Zone of the request (foreign key to the Zone table)

pooled_service

INTEGER

NO

0

boolean flag - did the request allow pooling? (Not a guarantee that the ride was actually pooled)

party_size

INTEGER

NO

0

Number of travelers/objects bundled within this request

estimated_od_travel_time

REAL

YES

0

Estimated travel time obtained from the skim (units: seconds)

person

INTEGER

YES

Person(person)

Person ID that requested the trip, if it is a TNC mode request. NULL if it is an on-demand delivery or e-scooter request. (foreign key to the Person table)

assigned_vehicle

INTEGER

YES

Vehicle(assigned_vehicle)

Shared mobility vehicle assigned to serve the request. Unassigned request if NULL. (foreign key to the Vehicle table)

number_of_attempts

INTEGER

NO

0

Number of attempts made in finding a candidate vehicle for assigning to the request. Each attempt is made every 30 seconds until the TNC_MAX_ASSIGNMENT_TIME threshold is hit.

fare

REAL

YES

0.0

Fare collected in serving the request (units: $USD)

distance

REAL

YES

0.0

Distance traveled in serving the request (units: miles)

discount

REAL

YES

0.0

Discount provided when trip is assigned to a vehicle by operator (units: $USD)

service_type

INTEGER

YES

0

Service type requested based on the available options defined in @@ TNC_Service_Types @@

seating_type

INTEGER

YES

0

Number of minimum seats requested for the vehicle, regardless of how many seats will be occupied by request.

(* - Primary key)

The SQL statement for table and index creation is below.

CREATE TABLE "TNC_Request" (
  "TNC_request_id" INTEGER NOT NULL PRIMARY KEY,
  "request_time" REAL NULL DEFAULT 0,
  "reserve_time" REAL NULL DEFAULT 0,
  "assignment_time" REAL NULL DEFAULT 0,
  "pickup_time" REAL NULL DEFAULT 0,
  "dropoff_time" REAL NULL DEFAULT 0,
  "access_walk_duration" REAL NULL DEFAULT 0.0,
  "egress_walk_duration" REAL NULL DEFAULT 0.0,
  "origin_location" INTEGER NOT NULL DEFAULT 0,
  "destination_location" INTEGER NOT NULL DEFAULT 0,
  "origin_link" INTEGER NOT NULL DEFAULT 0,
  "destination_link" INTEGER NOT NULL DEFAULT 0,
  "adjusted_origin_location" INTEGER NOT NULL DEFAULT 0,
  "adjusted_destination_location" INTEGER NOT NULL DEFAULT 0,
  "adjusted_origin_link" INTEGER NOT NULL DEFAULT 0,
  "adjusted_destination_link" INTEGER NOT NULL DEFAULT 0,
  "service_mode" INTEGER NOT NULL DEFAULT 0,
  "origin_zone" INTEGER NOT NULL DEFAULT 0,
  "destination_zone" INTEGER NOT NULL DEFAULT 0,
  "pooled_service" INTEGER NOT NULL DEFAULT 0,
  "party_size" INTEGER NOT NULL DEFAULT 0,
  "estimated_od_travel_time" REAL NULL DEFAULT 0,
  "person" INTEGER NULL,
  "assigned_vehicle" INTEGER NULL,
  "number_of_attempts" INTEGER NOT NULL DEFAULT 0,
  "fare" REAL NULL DEFAULT 0.0,
  "distance" REAL NULL DEFAULT 0.0,
  "discount" REAL NULL DEFAULT 0.0,
  "service_type" INTEGER NULL DEFAULT 0,
  "seating_type" INTEGER NULL DEFAULT 0,

  CONSTRAINT "person_fk"
    FOREIGN KEY ("person")
    REFERENCES "Person" ("person")
    DEFERRABLE INITIALLY DEFERRED,
  CONSTRAINT "assigned_vehicle_fk"
    FOREIGN KEY ("assigned_vehicle")
    REFERENCES "Vehicle" ("vehicle_id")
    DEFERRABLE INITIALLY DEFERRED);