a web app to compute travel CO2eq for different means of transport worldwide

The work presented here is independent and not-for-profit. This work has been carried out on a voluntary basis.

The aim of this web app is to present precise carbon inventories per passenger for each mode of transport and each journey. These results enable users to make informed choices in the context of reducing their greenhouse gas emissions to mitigate climate change. To put these results into context, total net yearly per-capita emissions should not exceed 2 tons CO2eq in 2050 to limit global warming below +2°C.

How the emissions are calculated?

To calculate CO2 equivalent emissions per person, we multiply the distance of a journey (km) by the corresponding emission factor (mass of CO2 equivalent per person per km) of a mean of transport. For a mutlistep journey, these emissions are summed over the different steps:

$$CO_2eq = \sum_{step} Distance(km) \times Emission \: Factor(kgCO_2eq / km) $$

Estimation of distances

Mean of Transport	Distance
Train	OpenStreetMap network
Car & Bus & eCar	OpenStreetMap network
Bike route	OpenStreetMap network
Plane	Geodesic distance and average detour
Ferry	Approximation of shortest path

What do emission factors depend on?

Mean of Transport	Variable
Train	Visited countries
Bus	-
Car	Number of passengers
Electric car	Visited countries & Number of passengers
Bike route	-
Plane	Distance of journey
Ferry	(not yet) User-specified parameters

Emissions factors consider usage (linked to the manufacture and use of energy to move the vehicle) as well as infrastructure and vehicle construction where these are significant. The table below summarizes the types of emissions taken into account by lowtrip. Empty cells mean that the related emissions did not contribute significantly to the result and are therefore excluded to facilitate understanding and readability for the user.

Mean of Transport	Usage	Vehicle construction	Infrastruture construction
Train	✅		✅
Car & Bus & eCar	✅	✅
Bike route		✅	Not found
Plane	✅
Ferry	✅	Not found	Not found

All assumptions, data and sources used are available in the methodology document.

How to launch the app?

Prerequisites

Have python & node installed

Launch the backend

Go in backend folder :

cd backend

Install the dependencies :

pip install -r requirements.txt

Launch :

gunicorn app:app

Launch the frontend

Go in frontend folder :

cd frontend

Install the dependencies :

npm install

Launch :

npm start

How to cite this work ?

Bonnemaizon, Xavier, Ni, Clara, Gres, Paola & Pellas, Chiara. lowtrip (2024). https://lowtrip.fr