Aide et accessibilité : Carbon footprint calculator

The LiA route calculator enables you to compare the environmental impact of your trip, when you use public transport or your car.

The CO2 production calculation is carried out using the distances travelled and average carbon producing coefficients for each mode of transport.

The results correspondent to the evaluation of all gas emissions that contribute to the greenhouse effect, produced  for 1 year for the mode of transport and evaluated as "CO2 equivalent" kilos. The rest comes from oil, coal, etc.. generates some CO2 emissions.


Coefficients used by different transport modes:

  • Car : 301.7 kg eq. CO2
  • Bus : 77.7 kg eq. CO2
  • Tramway : 16.7 kg eq. CO2
  • Metro : 23.1 kg eq. CO2
  • Coach : 77.7 kg eq. CO2
  • TER Train : 59.9 kg eq. CO2
  • TGV Train : 22.3 kg eq. CO2

Carbon coefficients used by the LiA  calculator (latest update: May 2010)


  • Car, bus, tramway and metro coefficients are from work carried out by the Agence de l'Environnement et de la Maîtrise de l'Energie (ADEME), in consultation with representatives of the French public transport operators. These coefficients are used by the ADEME ecocalculator (see links at bottom of page).
  • Because ADEME has no defined coefficient references for Coach mode, the LiA have chosen to use the same coefficient as for the bus.
  • Coefficients for TER and TGV trains are those established by the SNCF, which uses uses these particular coefficients for its ecocomparer (see links at bottom of page)

The coefficients used are only averages. In reality, newer cars pollute less than older cars and it is the same for buses, coaches and trains ... We must therefore consider the LiA carbon ratio as an indication of  size of the carbon savings made by taking public transport - bearing in mind that substantially different results could be obtained for the same journey depending on vehicles used and the calculation assumptions made.

Coefficients by transport mode used by the LiA computer are likely to evolve over time, especially with new reference coefficients communicated by ADEME or SNCF.

This page will then be updated.


For more information concerning carbon footprints and energy policies :