The "Tra?c and Granular Flow '07" conference was the seventh of a series of international conferences that started in 1995 in Julic .. h (Germany). Since then, the conference took place in Duisburg (1997), Stuttgart (1999), Nagoya (2001), Delft (2003) and Berlin (2005). The aim of TGF conferences is to facilitate the exchanges between various ?elds dealing with transport. When the conference was created, the ?elds that were represented were road tra?c and granular ?ow - hence the name of the series. Since then, the scope of the conference has been enlarged to include in particular collective motion in biology (molecular motors), a subject which turns out to have many connections with the two original ones. Transversal themes have emerged. For TGF07, a session was speci?cally devoted to the subject of networks. An important theme is also the one of self-propelled particles. It ranges from granular ?ows with anisotropic grains, to collective motion of animals, and to pedestrian tra?c. We were very happy to organize the 2007 occurrence of TGF in Orsay (France), at the University Paris-Sud.
The conference was organized mainly by the Laboratory of Theoretical Physics (LPT), with the help of the Labo- tory FAST (Fluides, Automatique et Syst' emes Thermiques) - these two la- ratories are both associated to the CNRS (Centre National pour la Recherche Scienti?que) - and of the GARIG Group at INRETS.