Review of sustainable public transport alternatives in low- and middle income cities

Rapid urbanisation in low- and middle-income countries (LMICs) is intensifying mobility challenges, including congestion, inefficient public transport systems, and growing environmental impacts. Identifying sustainable transport alternatives that can improve urban accessibility while reducing economic and environmental burdens has therefore become a critical policy priority. This study presents a systematic review of 110 peer-reviewed publications published between 2000 and 2025, following PRISMA-based screening and synthesis procedures, to evaluate the performance, sustainability outcomes, and contextual suitability of four major urban transport alternatives: bus rapid transit (BRT), formalised paratransit systems, non-motorised transport (NMT), and demand-responsive transit (DRT). Quantitative indicators, including capital cost, passenger capacity, travel-time reduction, emissions mitigation, and operational efficiency, were integrated with a qualitative socio-institutional analysis to assess the performance of real-world implementation in LMIC cities. The results show that BRT systems can reduce corridor travel times by approximately 20–35% and support passenger capacities of 8000–20,000 passengers per hour per direction, although their capital costs typically range from USD 5–25 million per kilometre, creating affordability constraints for many cities. Formalised paratransit systems, which currently account for a large share of urban mobility in many LMICs, demonstrate extensive spatial coverage and operational flexibility but require regulatory and institutional restructuring to improve safety and Reliability Conditions. Non-motorised transport interventions, including walking and cycling infrastructure, exhibit the highest cost-effectiveness and significant co-benefits in emissions reduction, public health, and short-distance accessibility. Meanwhile, demand-responsive transit platforms provide improved first- and last-mile connectivity and adaptive routing but remain constrained by digital infrastructure and operational scalability in many developing contexts. Overall, the findings indicate that no single transport solution universally addresses LMIC mobility challenges, highlighting the need for context-specific multimodal integration supported by governance capacity, institutional coordination, and data-driven transport planning. This review provides a consolidated evidence base to inform sustainable transport policy design and implementation strategies in rapidly urbanising cities.