In UK transport appraisal, equity impacts are scored qualitatively. However, the impacts of safety perceptions are not explicitly quantified, limiting the ability of current appraisal methods to capture how perceived safety influences travel behaviour, journey choices, and the wider time and cost consequences of trips that individuals choose not to make.
Drawing on complementary expertise in travel demand modelling, travel behaviour, and transport policy from Imperial College London, the University of Birmingham, and Northeastern University London, this project sets out to make such impacts visible within the Department for Transport’s WebTAG appraisal framework. By incorporating the effects of safety perceptions into transport appraisal, the project will enhance the evidence base for more equitable and inclusive transport investment decisions and improve understanding of the relationship between perceived safety, accessibility, and travel demand.
The project is led by Chio Fuseya, an MSc Transport with Data Science candidate at Imperial College researching transport equity, perception-based travel behaviour, and quantitative appraisal methods. She is advised by Dr Dilum Dissanayake, Associate Professor in Transportation Planning at the University of Birmingham, who contributes expertise in behavioural data analysis and discrete choice modelling and supports dissemination through her membership of the Department for Transport’s (DfT’s) Shadow Joint Analysis Development Panel.
Dr Ka Ho Tsoi, Assistant Professor in Transport Planning at Northeastern University London, advises on interview design and perception indicators and supports workshop facilitation through the Transport Planning Society. Academic oversight is also provided by Professor Aruna Sivakumar, Director of the Urban Systems Lab, whose expertise in econometrics and equity-focused modelling informs the appraisal approach, and Dr Jose Escribano, whose expertise in operational modelling and quantitative methods supports its technical development.
Research across several decades and countries has shown that women disproportionately manage the risk of harassment on public transport, adjusting routes, travel times, and modes to feel safer. More than 70% of women in London have changed, avoided, or paid more for a journey because of safety concerns (London Travel Watch, 2022), with implications for access to employment and wellbeing (POST, 2025). Transport institutions influence these risks through decisions on lighting, staffing, service provision, and the location of transport facilities, while appraisal determines how such interventions are assessed against their costs.
Personal security is already considered in transport appraisal as a distributional impact, including for women, older and younger people, people with mobility impairments, and minority ethnic groups. However, it is assessed qualitatively in the Appraisal Summary Table and is not included in the monetised costs and benefits used to calculate the Benefit-Cost Ratio (BCR). Consequently, safety benefits cannot be directly compared with benefits such as journey-time and cost savings that are already expressed in monetary terms.
This creates a potential appraisal gap in which interventions that improve perceived safety may be undervalued because their benefits are not captured using the same metrics as other transport benefits.
This project develops the Perception Equity Framework (PEF), a proof-of-concept method that uses existing survey and travel data to estimate how safety perceptions influence travel choices. It will quantify the resulting impacts on travel demand, travel time, and travel cost, providing measures that are currently absent from appraisal. The framework will also demonstrate how these indicators could be incorporated into existing WebTAG guidance using established appraisal methods.
The project will be delivered in four stages.
The first stage will be to review existing travel survey data and WebTAG guidance and to develop a practitioner interview questionnaire. The second will be to carry out structured interviews with 12 to 15 practitioners from the DfT, Transport for London, the Transport Planning Society, regional transport bodies, and major consultancies. These interviews will examine how safety perceptions and suppressed journeys are currently considered in appraisal and identify barriers to incorporating them more systematically.
The findings will inform the third stage, which will develop the Perception Equity Framework (PEF) and demonstrate its application through a worked example, such as the effects of improved lighting on a specific demographic group. The stage will also set out how the framework could be incorporated into existing WebTAG methods.
The final stage will focus on dissemination through a workshop co-facilitated with the Transport Planning Society and a case study presentation to the DfT’s Joint Analysis Development Panel.
The project will produce a proof-of-concept framework and worked example, a report summarising practitioner perspective on current appraisal gaps and the potential for new perception and equity metrics, and a dissemination workshop and case study presentation.
The longer-term aim is to provide a stronger quantitative basis for assessing how perceived safety affects transport equity. The findings could inform future development of WebTAG guidance and support a wider discussion among practitioners and researchers on incorporating perceptions into transport appraisal.