Measuring the Social Value of Public Transport Investment in Nigeria: A Wellbeing Economics Approach

Conventional cost-benefit analysis of public transport investment captures economic efficiency but systematically undervalues social and wellbeing outcomes including social inclusion, health, mental wellbeing, and community cohesion that are particularly significant for low-income populations. This study applies a wellbeing economics framework to measure the social value of public transport investment in Nigeria, developing original measurement instruments and valuation methods adapted to the Nigerian socioeconomic context. The research adopts a mixed methods design combining a quasi-experimental evaluation of the Lagos BRT Phase 2 extension (comparing beneficiary and control communities before and after service introduction), a stated preference wellbeing valuation survey with 800 respondents, and a social value accounting methodology adapted from the Social Return on Investment framework. Wellbeing outcomes measured include subjective wellbeing, social connectedness, access to economic opportunities, health service utilisation, and time use distributions. Difference-in-differences estimates from the quasi-experiment show significant positive BRT impacts on household subjective wellbeing scores (effect size 0.31 standard deviations), social connectedness indicators, and female labour market participation. Social value accounting demonstrates that conventional economic appraisal captures only 44 percent of the total social value generated by the investment when wellbeing dimensions are incorporated. The study addresses a fundamental measurement gap in Nigerian transport investment appraisal methodology and contributes original wellbeing valuation instruments validated for sub-Saharan African urban populations. Policy recommendations include mandatory social value assessment in transport project appraisals above a threshold cost. Keywords: social value, wellbeing economics, public transport investment, Lagos BRT, transport appraisal.