Toward sustainable electric bus operations: a multidimensional structural model for future mobility management

The transition toward low-carbon transportation has accelerated the adoption of electric mobility in urban transport systems. Unscheduled electric bus services, including charter, tourism, and demand-responsive operations, face operating conditions that differ from fixed-route public transport, particularly variable demand, irregular routes, changing charging opportunities, and coordination across technical, service, cost, and sustainability functions. Existing studies commonly address vehicle technology, charging, scheduling, cost, or environmental performance as separate optimization problems. This study develops and validates the Sustainable Electric Vehicle BUS Model (SEVBUS), an operational measurement architecture designed specifically for unscheduled electric bus services. Its novelty lies in translating fragmented technical and managerial evidence into 48 observable indicators, 19 first-order factors, and a higher-order construct that can be empirically assessed within a single measurement framework. The empirical study was conducted from January to April 2026 in Bangkok, Thailand, involving operators of unscheduled bus services. A sequential instrument-development process comprised structured literature synthesis, indicator screening, item-objective congruence assessment, Delphi validation with 13 experts, and a questionnaire survey of 400 stakeholders. Participants were selected through purposive criterion-based sampling based on their direct knowledge or experience in unscheduled electric bus operations. The study records report an initial pool of 96 candidate indicators, of which 48 were retained. The final sample included 280 drivers, 50 operation control center staff, 50 station or service staff, and 20 operational or fleet managers. Expert agreement was statistically significant (Kendall’s W = 0.438, p  p  < 0.001), indicating statistically significant associations among related but empirically distinguishable operational domains rather than directional or causal effects. The principal contribution of SEVBUS is methodological: it provides a validated multidimensional measurement architecture for examining unscheduled electric bus operations within the studied context of Bangkok, Thailand. Its practical effectiveness as a diagnostic, benchmarking, or decision-support tool remains to be demonstrated through field implementation, independent-sample validation, and objective operational data.