According to University of Paris researchers, the new (2007) Paris tramway (light rail or streetcar) along the south boulevards des Maréchaux has attracted, at most, 3 percent of its ridership from cars. This finding is made in a paper entitled Paris: un tramway nommé désir (Paris: A Streetcar Named Desire), published in August 2007 by Rémy Prud’homme, Martin Koenig, Pierre Kopp. The authors note that this small modal shift “once again shows the limits of modal shift strategies” (our liberal interpretation of the French).
While traffic along the boulevard has been reduced, this has been accomplished by narrowing the capacity and forcing traffic to parallel roadways. The result has been to increase traffic congestion and, as occurs when traffic becomes slower and more erratic, increase fuel consumption, which of course leads to higher greenhouse gas emissions. It is estimated the tramway has resulted in a net increase of nearly 40,000 tonnes of CO2 annually.
Finally, the social costs of the project are estimated to have exceeded the benefits.