8. Fare Definitions (fare_attributes.txt & fare_rules.txt)
These files are optional in a GTFS feed, but any rules specified must reference a fare attributes record.
These two files define the types of fares that exist in a system,
including their price and transfer information. The attributes of a
particular fare exist in fare_attributes.txt, which has the
following columns.
| Field | Required? | Description |
|---|---|---|
fare_id | Required | A value that uniquely identifies a fare listed in this file. It must only appear once in this file. |
price | Required | This field specifies the cost of the fare. For instance, if a trip costs $2 USD, then this value should be either 2.00 or 2, and the currency_type should be USD. |
currency_type | Required | This is the currency code that price is specified in, such as USD for United States Dollar. |
payment_method | Required | This indicates when the fare is to be paid. 0 means it can be paid on board, while 1 means it must be paid before boarding. |
transfers | Required | The number of transfers that may occur. This must either be empty (unlimited) transfers, or the number of transfers. |
transfer_duration | Optional | This is the number of seconds a transfer is valid for. |
The following table shows the specification for fare_rules.txt,
which defines the rules used to apply a fare to a particular trip.
| Field | Required? | Description |
|---|---|---|
fare_id | Required | This is the ID of the fare that a rule applies to as it appears in fare_attributes.txt. |
route_id | Optional | The ID of a route as it appears in routes.txt for which this rule applies. If there are several routes with the same fare attributes, there may be a row in fare_rules.txt for each route. |
origin_id | Optional | This value corresponds to a zone_id value from stops.txt. If specified, this means a trip must begin in the given zone in order to qualify for this fare. |
destination_id | Optional | This value corresponds to a zone_id value from stops.txt. If specified, this means a trip must begin in the given zone in order to qualify for this fare. |
contains_id | Optional | This value corresponds to a zone_id value from stops.txt. If specified, this means a trip must pass through every contains_id zone for the given fare (in other words, several rules may need to be checked). |
Note that aside from fare_id, all fields are optional in this file.
This means some very complex rules can be made (especially when
transfers come into the calculation). The following URL has discussion
about different rules and some complex fare examples:
https://code.google.com/p/googletransitdatafeed/wiki/FareExamples
Refer to Calculating Fares for discussion about the algorithm for calculating fares for trips both with and without transfers.
Sample Data
The following data is taken from the TriMet GTFS feed
(https://openmobilitydata.org/p/trimet). Firstly, the data from the
fare_attributes.txt file.
fare_id | price | currency | payment_method | transfers | transfer_duration |
|---|---|---|---|---|---|
| B | 2.5 | USD | 0 | 7200 | |
| R | 2.5 | USD | 1 | 7200 | |
| BR | 2.5 | USD | 0 | 7200 | |
| RB | 2.5 | USD | 1 | 7200 | |
| SC | 1 | USD | 1 | 0 | |
| AT | 4 | USD | 1 | 0 | |
| VT | 0 | USD | 1 | 0 |
The data from the fare_rules.txt file is shown in the following
table.
fare_id | route_id | origin_id | destination_id | contains_id |
|---|---|---|---|---|
| B | B | B | ||
| R | R | R | ||
| BR | B | B | ||
| BR | B | R | ||
| RB | R | B | ||
| RB | R | R | ||
| SC | 193 | |||
| SC | 194 | |||
| AT | 208 | |||
| VT | 250 |
In this sample data, TriMet have named some of their fares the same as
the zones specified in stops.txt. In this particular feed, bus stops
have a zone_id of B, while rail stops have R.
The fares in this file are as follows:
- Fare
B. If you start at a bus stop (zone_idvalue ofB), you can buy your ticket on board (payment_methodof0). You may transfer an unlimited number (empty transfers value) for 2 hours (transfer_durationof7200). The cost is $2.50 USD. - Fare
R. If you start at a rail stop, you must pre-purchase your ticket. You may transfer an unlimited number of times to other rail services for up to 2 hours. The cost is $2.50 USD.
The BR fare describes a trip that begins on a bus then transfers to
a rail service (while RB is the opposite). This fare is not be
matched if the passenger does not travel on both, as all contains_id
values must be matched in order to apply a fare.
The other fares (SC, AT and VT) all apply to their
respective route_id values, regardless of start and finish stops.
Tickets must be pre-purchased, and transfers are not allowed. The VT
fare (which corresponds to TriMet's Vintage Trolley) is free to ride
since it has a price of 0.
Assigning Fares to Agencies
One of the extensions available to fare_attributes.txt is to include
an agency_id column. This is to limit a specific fare to only routes
from the specified agency, in the case where a feed has multiple
agencies.
This is useful because there may be two agencies in a feed that define
fares with no specific rules (in other words, the fare applies to all
trips). If the price differs, then GTFS dictates that the cheapest fare
is always applied. Using agency_id means these fares can be
differentiated accordingly.
For more information about this extension, refer to the Google Transit GTFS Extensions page at https://support.google.com/transitpartners/answer/2450962.