Developing two-dimensional indicators of transport demand and supply to promote sustainable transportation equity
Patrick Ballantyne; Gabriele Filomena; Francisco Rowe; Alex Singleton (2024). Computers, Environment and Urban Systems, 113, 102179. DOI: 10.1016/j.compenvurbsys.2024.102179
Abstract
Inadequate supply of transport infrastructure is often seen as a barrier to a sustainable future for cities globally. Such barriers often perpetuate significant inequalities in who can and who cannot benefit from sustainable transport opportunities, and as a result there is momentum for transformative urban planning to promote sustainable transportation equity. This study introduces a new set of two-dimensional indicators, merging elements of supply and demand, to identify barriers and imbalances in sustainable transport equity. The accessibility indicators, which are generated for bus, rail, and cycle infrastructure, consider the proximity of administrative areas to good quality transport infrastructure, as well as mode-specific demand, to clearly identify areas where the supply of infrastructure is inadequate to support local populations. We present a policy case study for Liverpool City Region, which demonstrates how these indicators can be used in an analytical framework to support transformative urban planning in long-term. In particular, the indicators reveal policy priority areas where demand for sustainable transport is greater than supply, as well as neighbourhoods where multiple transport inequalities are intersecting spatially, highlighting the need for specific types of infrastructure investment to promote sustainable transport equity (e.g. more frequent services, additional cycle paths). Our framework lays the foundations for improved decision-making in urban systems, through development of mode-specific sustainable transport indicators at small area levels, which harmonise elements of supply and demand for the first time.
Extended Summary
This research develops a novel two-dimensional transport accessibility framework that combines infrastructure supply with actual population demand to identify where sustainable transport improvements are most needed. The study addresses how urban areas can systematically identify barriers to sustainable transport equity by moving beyond traditional proximity-based accessibility measures to account for both infrastructure quality and local population engagement with different transport modes. The methodology calculates supply scores by measuring walking distances to bus stops, railway stations, and cycle infrastructure, whilst incorporating quality metrics such as service frequency and infrastructure standards. Demand is measured using census commuting data adjusted with National Travel Survey trends to account for post-pandemic travel behaviours. These supply and demand components are combined into composite indicators that highlight areas where demand exceeds supply across bus, rail, and cycling networks. Applied to Liverpool City Region, the framework reveals significant spatial inequalities in transport accessibility. The research identifies priority areas such as Barnston, Everton, and parts of Sefton where multiple transport inequalities intersect, creating compound disadvantages for residents. The indicators successfully pinpoint neighbourhoods where residents have relatively high demand for sustainable transport but face poor access to quality infrastructure. For bus services, many areas show adequate proximity but suffer from infrequent services, whilst rail accessibility varies dramatically across the region with only 14% of people able to access train stations within reasonable walking distances. Cycling infrastructure presents the greatest challenges, with significant mismatches between demand and supply, particularly in outer suburban areas. The two-dimensional approach enables policymakers to distinguish between different types of interventions needed - whether areas require additional infrastructure, improved service quality, or both. This precision supports more targeted investment decisions as Liverpool City Region implements its £710 million sustainable transport settlement funding. The framework’s broader significance lies in providing evidence-based tools for urban planners and transport authorities to promote sustainable transport equity. By identifying where existing demand is constrained by inadequate supply, the methodology supports transitions away from car dependency towards more sustainable urban mobility systems, contributing to both climate goals and social equity objectives in urban planning.
Key Findings
- Two-dimensional indicators combining transport supply and demand successfully identify spatial mismatches in sustainable transport accessibility across urban areas.
- Liverpool City Region shows significant transport inequalities, with only 14% of residents able to access railway stations within walking distance.
- Multiple transport inequalities intersect spatially in areas like Barnston and Everton, requiring targeted multi-modal infrastructure investments.
- Cycling infrastructure presents the greatest supply-demand mismatches, with substantial gaps between existing demand and available quality infrastructure.
- The framework enables precise targeting of interventions, distinguishing between needs for additional infrastructure versus improved service quality.
Citation
@article{ballantyne2024developing,
author = {Patrick Ballantyne; Gabriele Filomena; Francisco Rowe; Alex Singleton},
title = {Developing two-dimensional indicators of transport demand and supply to promote sustainable transportation equity},
journal = {Computers, Environment and Urban Systems},
year = {2024},
volume = {113},
pages = {102179},
doi = {10.1016/j.compenvurbsys.2024.102179}
}