The proceedings of seminar P contain the following papers: Some Theoretical Difficulties in Using Equilibrium Assignment in Signal-Controlled Road Networks (Heydecker, BG); Modelling Dynamic Junction Behaviour (Budd, AM and Mackenzie, J); The Effect of Spatial Detail on Equilibrium Assignment Results (Jansen, GRM and Bovy, PHL); Development and Application of a Park-and-Ride Model (le Clercq, F); Research on Household Car Ownership (Bates, JJ Roberts, M); A behavioural Model of Household Ownership and Use of Motor Vehicles and its Application for Aggregate Forecasting (Ben-Akiva, M, Manski, CF and Sherman, L); Computing in Transport Planning in the 1980's: a US Perspective (Manheim, M, Gonzalez, S, Litinas, N and Salomon, I); Computing in Transport Planning in the 1980's: A British Perspective (Wootton, HJ); RHTM Trip Distribution Investigation (Kirby, HR, Gunn, HF, Murchland, JD and Whittaker, JC); RHTM Base Year and Future Year Trip Matrices (Case, DJ and Catling, I); Uncertainty-the Errors of the Forecast of an Inter-Urban Traffic Model (Ashley, DJ and Shewey, P); An Analysis of Airport Passenger Surface Access Mode Choice at a Major British Provincial Airport (Sheldon, RJ). (Continued on TRIS 342936).