Taking passenger info into account.
For trains and flights, if the user is going for a premium economy, business or first class, then he is somewhat more responsible for the amount of Carbon Footprint released since otherwise, more economy seats could have been adjusted in the same space. Let's say if a Business Class seat occupies 1.5 times the space in Economy class, then the person travelling in Business Class is releasing 50% more carbon footprint than the one who is travelling in the Economy Class. Same goes with trains.
For cars, if the user is opting for carpool, then the per head liability decreases. We should find a way to take all this information into account.
Edited by Chirag Arora