Delay-Induced Passenger Electricity Use in Public Transport: A Critical Review and Analytical Framework

Public transport unreliability is usually evaluated through travel time, service quality and operational energy use, while the electricity associated with passengers’ digital behaviour during disruptions remains largely outside transport-energy assessments. This study introduces Delay-Induced Passenger Electricity Use (DPEU) as a counterfactual framework for examining whether unreliable service changes passenger-related digital electricity consumption relative to equivalent normal-service conditions. A critical review integrates evidence on transport reliability, passenger accumulation, digital behaviour, smartphone electricity demand and supporting ICT infrastructure. The framework represents passenger exposure dynamically and distinguishes additional digital activity from activity that is temporally displaced or suppressed. An order-of-magnitude real-system application is developed for GTT Line 4 in Turin using a documented frequency-based service baseline and analytical headway perturbations rather than reconstructed historical disruption events. Parameter uncertainty is propagated through 300,000 Monte Carlo combinations. Device-side DPEU has theoretical bounds of approximately −4.05 to +4.05 Wh per disruption event, while the central 95% of simulated outcomes lies between approximately −1.37 and +1.36 Wh. Sensitivity analysis identifies the counterfactual behavioural difference as the principal determinant of DPEU, particularly its direction, while behavioural intensity, device power, and passenger exposure jointly determine its absolute magnitude. The results indicate that event-level DPEU is small relative to public-transport operational energy use. More importantly, the analysis provides a transparent approach for examining whether a delay-induced electricity effect exists, estimating its possible magnitude and uncertainty, and identifying the empirical observations required for future validation and practical assessment.