Carbon footprint of the journey planner

The route planner compares the environmental impact of the proposed journey with that of the same journey made by car.

CO2 production is calculated based on the distances travelled using each means of transport, as well as the average carbon production coefficients for each means of transport gCO2e/

gCO2e: grammes of CO2 equivalent

Coefficients used by different modes of transport

  • Car: 86.9 kg CO2e
  • Tram: 1.2 kg CO2e
  • Subway: 1.42 kg CO2e
  • Train: 3.87 kg CO2e
  • TER regional train: 3.87 kg CO2e
  • TGV high-speed train: 55.9 kg CO2e
  • Bus: 55.9 kg CO2
  • Coach: 25.16 kg CO2

The car, bus, tram and metro coefficients are based on work carried out by the French Environment and Energy Management Agency (ADEME), in consultation with representatives of French public transport operators. Note that these coefficients are used by ADEME’s eco-calculator.

Since ADEME’s work has not established a benchmark coefficient for coaches,

the trip planner uses the same coefficient as for a bus.

The TER and TGV train coefficients are those established by SNCF, which uses these coefficients for its eco-comparator. 

The coefficients used are only averages: recent cars pollute less than older cars, the same applies for buses, coaches and trains… This means the carbon ratio should only be considered an indicator of the order of magnitude of the carbon savings made by using public transport – bearing in mind that drastically different results might be obtained for the same journey depending on the calculation settings used.

Public transport distances are calculated as near as possible to the actual route by adding the distances of each section from stop to stop.

Private car distances are calculated based on the road graph