There are three principal components to the research presented in this thesis: a video-observation study of pedestrian behaviours and interactions with traffic, leading to the development of an agent-based digital simulation, and demonstrating the potential of this simulation for designing pedestrian-centric interventions in the streetscape. The long-term objective is to devise streetscapes that responsively adapt to the needs of pedestrians.

Since the advent of car culture in the late 1930s, the approaches to street design have prioritised efficient motorised traffic flow, restricting walking and neglecting the pedestrian point of view. In recent years, however, a growing interest in making urban spaces more pedestrian-friendly has emerged, popularising concepts such as walkability, shared space, and traffic calming. These approaches aim to promote active travel and reduce car dependency in order to mitigate congestion, pollution, accidents and other harms.

Urban studies have concentrated primarily on pedestrian-only zones and utilised spatial features as a way to reach pedestrian-friendly streets. Meanwhile, transport studies have tended to approach the street from a throughput and vehicle-oriented stance. Despite these endeavours, pedestrian-oriented approaches appear to lack systematic consideration of pedestrian behaviours as they interact with motor vehicles and street infrastructure. My PhD research differs from prior studies by focusing on these behaviours and interactions to support a pedestrian-oriented street mobility system.

The current design of streets communicates to pedestrians via its structures and signs, such as barriers, crossings, and lights, while its capacity to respond and adapt is minimal. In contrast, this thesis argues that, since the street environment is inherently dynamic, we should analyse its dynamics and design the street to be responsive. Through responsiveness, my aim is to increase the convenience of pedestrian movement whilst creating a safe experience.

This PhD asks the question 'how to design a pedestrian-centric street system that dynamically manages street mobility?'. The research takes a practice-based and reflective approach, designing agent-based simulations based on a qualitative observational study. Designing a simulation accomplishes two things: 1) it creates a space for implementing and evaluating possible design interventions, and 2) it prompts new insights into the behavioural processes of pedestrians. My research has followed an iterative cycle in line with second-order cybernetics: in two feedback loops, the first study informed the second study while the second informed the first.

The video observation of street behaviours particularly explored pedestrian decision and interaction processes, identifying pedestrians’ own observational strategies and their varying levels of risk-taking. These aspects are reflected in the simulation.

The first chapter introduces the pedestrian issues on the street and sets out the key concepts in pedestrian-centric street design. The second chapter examines the literature and existing practice that addresses pedestrian and vehicle interactions on the street. Chapter three sets out the theoretical framework and the following chapter describes the methodology. The three subsequent chapters present the following studies: (1) understanding the context by conducting qualitative video observation in a real street environment to observe and document the relations between streets, pedestrians and vehicles; (2) creating an artificial pedestrian society for simulation purposes, using agent-based modelling, both to refine the understanding developed through video analysis and to create a platform for experimentation; (3) design and implementation of prototype responsive interventions within the simulation, focusing on localised changes in the environment to empower pedestrians. The last chapter reflects on these projects by discussing the research contributions in terms of methods, techniques, and practices. The methodological innovation includes combining qualitative and computational tools as well as the use of simulation and video analysis in an iterative and reflexive cycle. Theoretical contributions include evaluating streets through pedestrian dynamics, creating a taxonomy of existing pedestrian interventions according to their spatial and temporal impacts, and rethinking the street as a responsive environment. The practical component advances the technical state of the art by expanding the capabilities of pedestrian agents when negotiating with vehicles and making crossing decisions and demonstrates the potential for designing novel interventions in the streetscape, including those that respond to pedestrian behaviour. The last chapter, also, emphasises the role of reflective design practice and the place of simulation within it.