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- Report n°6: Urban Public Transport
Report n°6: Urban Public Transport
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Table of contents
- Public transport and sustainable development
Public transport and sustainable development
Our purpose is not to provide an exhaustive review of the relationship between urban mobility and energy expenditure, atmospheric pollution and solidarity within society, but simply to examine some of the major points supporting the legitimacy of public policies in favour of the development of collective urban transport systems.
The first point to remember is that the energy efficiency of modes of urban transport, that is the quantity of energy needed to move a person over a given distance, differs considerably from one mode to another: a private car consumes 60 grammes of oil equivalent per person and per kilometre whereas the metro, tram or train only consume 20, and a bus 25. Emission of atmospheric pollutants is proportional: a private car emits 30 to 35 grammes of CO (carbon monoxide) and 1.5 grammes of NOx (nitrogen oxides) per person and per kilometre. Buses emit respectively 0.5 and 0.005 grammes of these substances.
In the greater Paris area (Ile-de-France), based on existing traffic figures, a kilogramme of oil equivalent can move 18 passengers x km (product of the number of passengers by the number of kilometres travelled), compared to 37 by bus, 180 by tram and 130 with the metro or suburban railway line (RER).
Furthermore, the surface area required to transport city dwellers by private car is also much greater than what is necessary for the movements of public transport vehicles, since for an equivalent amount of traffic, private cars use 50 times more space than a fully occupied bus. When there is a shortage of public space because urban construction is antiquated, devices used to maintain the possibility of travel by private car are extremely costly (tunnels, viaducts) and end up being as expensive as the cost of constructing metro lines, for a capacity which is no greater and for use limited to users of private cars, hence to the exclusion of "captives".