The fourth session has something to do with the traction of tires, but specifically it is entitled, “The Role of the Pavement,” and for this session we have three speakers. I really would like to mention just a little bit about how speakers were selected because I think in the case of our three speakers of this session we find first that they are all from the British Empire. This does not imply that there are no authorities on the subject in the United States or in Germany or elsewhere. The original plan, and the title of the conference is, “The Physics of Tire Traction.” When it comes to the physics of tire traction, one has to, of course, define some terms within that bound and we chose to look at mechanisms. Inevitably we got down to the details of the interaction between the tire and the road. The three speakers of this session were selected in particular because they have had some of the newer works available, which in our judgment have high potential for aiding understanding of the complex interaction between the tire and road and for generating a very good discussion here. These papers have breadth and at the same time depth and will make a very fine contribution to the proceedings from this conference. The three speakers are Dr. Yandell, Mr. Schonfeld, and Dr. Williams.