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CO₂ Emissions calculation

Contact Info

  • Digitransit Team
  • Entur AS

Documentation

The emission module enables import of CO₂ Emissions data which OTP can use to decorate itineraries and itinerary legs. Emissions data is loaded during the graph build process. OTP supports two data import formats (yet to be standarized).

  • The Route format provided by HSL decorates each route with a average co2 emission per kilometers per person. The input parameters are route_id, avg_co2_per_vehicle_per_km and avg_passenger_count.
  • The Trip format provided by Entur decorates each trip hop. The plan is to expand this to include service date. This allows the emission provider to calculate acurate data down to each trip departure (except departures operated by more than one vehicle). The input parameters are trip_id, from_stop_id, from_stop_sequence and co2.

Emission input data files

OTP can load emission data files as part of a GTFS bundle(zip, composite resource or directory) and from separate files provided individually.

  • If provided as part of a GTFS bundle the file MUST be named emissions.txt.
  • If provided as a standalone file the file must be listed in the build-config.json and the file name MUST include the word '"emission"' and the extension must be .csv or .txt. The configuration must include a feedId for each file. This feedId is used to match the the trip id tho the transit feed. Both NeTEx and GTFS feeds are supported.

Both formats are supported as part of a GTFS bundle and as standalone files.

Emission route format input data files

(by the Digitransit team)

The emissions are represented in grams per kilometer (g/Km) unit.

Emission file has the following columns:

CSV Header Description
route_id Route id
avg_co2_per_vehicle_per_km Average carbon dioxide equivalent value for the vehicles used on the route at grams/Km units.
avg_passenger_count Average passenger count for the vehicles on the route.

For example:

route_id,avg_co2_per_vehicle_per_km,avg_passenger_count
1234,123,20
2345,0,0
3456,12.3,20.0

Emission trip hop format input data files

(by the Entur team)

The emissions are represented in grams per kilometer (g/Km) unit.

Emission file has the following columns:

CSV Header Description
trip_id The GTFS trip id or the NeTEx ServiceJourney id
from_stop_id The GTFS stop id or the NeTEx Quay id. This is use together with the from_stop_sequence to match the stop. If the emissions data does not match the given transit feed, then the row is dropped and an issue is added to the build report.
from_stop_sequence The boarding stop sequence number in the trip stop pattern. The first stop is number one(1), not zero(0).
co2 Average carbon dioxide equivalent value for the vehicles used on given trip hop starting at the given stop. The unit is grams per person per hop.

For example:

trip_id,from_stop_id,from_stop_sequence,co2
Trip:3,Stop:A,1,90.456
Trip:3,Stop:A,2,130.483
Trip:3,Stop:A,3,172.646

Configuration

To enable this functionality, you need to enable the "Emission" feature in the otp-config.json file.

//otp-config.json
{
  "Emission": true
}

Include the emissions object in the build-config.json file. The emissions object should contain parameters called carAvgCo2PerKm and carAvgOccupancy. The carAvgCo2PerKm provides the average emissions value for a car in g/km and the carAvgOccupancy provides the average number of passengers in a car.

Example configuration

// build-config.json
{
  "emission" : {
    "carAvgCo2PerKm" : 170,
    "carAvgOccupancy" : 1.3,
    "feeds" : [
      {
        "feedId" : "MY",
        "source" : "https://my.org/emissions/latest"
      }
    ]
  }
}

Overview

Config Parameter Type Summary Req./Opt. Default Value Since
carAvgCo2PerKm gram The average CO₂ emissions of a car in grams per kilometer. Optional "170g" 2.5
carAvgOccupancy double The average number of passengers in a car. Optional 1.3 2.5
feeds object[] List of emission feeds. Optional 2.8
      feedId string Specify the feed id to use for matching transit ids in the emission input data. Required 2.8
      source uri Specify the feed source url. Required 2.8

Details

feeds

Since version: 2.8 ∙ Type: object[] ∙ Cardinality: Optional
Path: /emission

List of emission feeds.

Changelog

OTP 2.5

  • Initial implementation of the emissions calculation. Support for the route input data format by Digitransit.

OTP 2.8

  • Support for the trip input data format by Entur and for standalone input files.