transit agencies table structure

The Transit_agencies table holds information on all the transit agencies for which there are transit services included in the model. information for these agencies include the GTFS feed (feed_date) and operation day (service_date) for which services were imported into the model.

Encoding of ids for transit agencies, routes, patterns and trips follows a strict encoding that allow one to trace back each element to its parent (Agency->Route->Pattern->Trip). This encoding follows the following pattern: AARRRPPTTT. Since this IDs are always integer, those corresponding to agencies 1 through 9 will omit the first 0 in the ID pattern shown above.

Many fields are not used during POLARIS simulation, and are stored only so a GTFS export after editing remains consistent with the GTFS originally imported. These fields are marked with “Not used by POLARIS” in the comments below.

Table Structure

Field	Type	NULL allowed	Default Value	Foreign key	Description
agency_id*	INTEGER	NO			ID of the agency. 1 is reserved for a dummy agency for walking links
agency	TEXT	NO			Display name of the agency. Defaults to the user-supplied identifier when overriding a single-agency feed; otherwise falls back to agency.txt’s agency_name.
feed_date	TEXT	YES			Release date for the GTFS feed used
service_date	TEXT	YES			The service date used for importing the GTFS feed
description	TEXT	YES			User notes (applied to every agency in the feed at import time)
agency_url	TEXT	YES			URL of the transit agency, as found in agency.txt. Not used by POLARIS
timezone	TEXT	NO	‘UTC’		Timezone of the transit agency, as found in agency.txt. All agencies in a feed share the same timezone per GTFS spec. Not used by POLARIS
lang	TEXT	YES			BCP 47 language code for the agency’s primary language, as found in agency.txt. Not used by POLARIS
phone	TEXT	YES			Voice telephone number for the agency, as found in agency.txt. Not used by POLARIS
fare_url	TEXT	YES			URL of a web page with fare information for the agency, as found in agency.txt. Not used by POLARIS
email	TEXT	YES			Email address actively monitored by the agency’s customer service, as found in agency.txt. Not used by POLARIS
gtfs_agency_id	TEXT	YES			Original agency_id string from the GTFS agency.txt file, Not used by POLARIS
gtfs_agency_name	TEXT	YES			Original agency_name from the GTFS agency.txt file. Not used by POLARIS

(* - Primary key)

The SQL statement for table and index creation is below.

create TABLE IF NOT EXISTS Transit_Agencies(
    agency_id           INTEGER NOT NULL  PRIMARY KEY AUTOINCREMENT,
    agency              TEXT    NOT NULL,
    feed_date           TEXT,
    service_date        TEXT,
    description         TEXT,
    agency_url          TEXT,
    timezone            TEXT    NOT NULL DEFAULT 'UTC',
    lang                TEXT,
    phone               TEXT,
    fare_url            TEXT,
    email               TEXT,
    gtfs_agency_id      TEXT,
    gtfs_agency_name    TEXT
);
create UNIQUE INDEX IF NOT EXISTS idx_polaris_transit_operators_id ON Transit_Agencies (agency_id);