Recent Preprint:
Levinson, David (2026) A General Theory of Access, Networks, and Cities
Abstract
A General Theory of Access, Networks, and Cities develops a framework for understanding how people reach valued opportunities and how those possibilities shape cities. Access is produced jointly by proximity and mobility, subject to costs, time windows, capacity, eligibility, and other constraints. The book brings familiar accessibility measures into a common mathematical structure, connecting the opportunities reachable within a given budget to the cost of reaching a specified number of opportunities. The framework extends across activities, transport modes, population groups, and physical and digital connections. It accounts for perceived access, reliability, safety, and the durability of access over time. Access Surplus links the costs of reaching opportunities with willingness to pay, providing a basis for valuing changes. Access gradients identify differences that can motivate movement, relocation, investment, and institutional responses. These mechanisms underpin a proposed account of the co-evolution of networks, land use, services, and rules. Drawing on transport and urban research, worked examples, and explicit propositions, the book sets out claims that can be tested against observed behaviour and urban change. It distinguishes the measurement of access from judgements about whose access should receive priority and how much is sufficient. The resulting framework supports the appraisal of transport and land-use policies through their effects on reachable opportunities, their distribution, and their persistence, providing a common analytical basis for questions of efficiency, equity, affordability, resilience, and sustainability.
The revised version of this book will be published in 2027 by Cambridge University Press, under a Green OA License.
