Following a suggestion made by M. Louis Armand of the Academie Française on the occation of the celebration in Brussels in June 1963 of the tenth anniversary of the ECMT, it was decided to organise an international meeting with participants from a variety of milieus (university, economic, transport) under the general theme "Theory and practice in transport economics".  This general theme is divided into a series of sub themes and the proceedings of this first symposium are presented in this book. Most of the presentations are in French.