The movement of pedestrians in the urban environment is vital for sustaining the social and economic relationships essential to the quality of life. To enable and encourage walking, suitable facilities must be available and planning and implementing such facilities requires an understanding of the characteristics of pedestrian movements. This thesis examined the factors which influence walking speeds, related them to current pedestrian modelling techniques and developed a series of new models to improve their estimation. A comprehensive review of current practices and procedures for modelling pedestrian walking speeds was carried out, identifying the factors currently used in existing methodology and highlighted its deficiencies. A significant finding from this study was that the industry-standard Highway Capacity Manual (HCM) methodology as it currently stands is not fully applicable to the types of walking environments that were the subject of this research (on-street walkways in UK shopping and Central Business District areas). It was shown there is a need to provide more holistic relationships which take into account the interactions between the characteristics of pedestrians and their walking environments (both built and natural). A number of additional factors which have a significant affect on walking speeds were identified and a series of new statistical relationships were developed which were also tested and validated against independent data. The predictive performance of the new models was also compared against the leading industry-standard methodology and shown to provide significantly better estimates. Future areas of research were also identified and described. The research thus provided a greater understanding of the dynamics affecting walking speeds, thereby helping to assist transport planners and engineers with the study and design of suitable pedestrian facilities.