Using system dynamics to explore shared mobility and sustainability connections

Shared mobility technologies promise new pathways toward sustainable transportation, yet concerns remain regarding their unintended consequences on urban mobility systems. While several studies have examined these impacts, most rely on linear cause-and-effect methodologies that fail to account for the complexity inherent in urban mobility. This study addresses this gap by applying qualitative system dynamics modeling to detect, describe, and analyze the implications of shared mobility on urban mobility sustainability. Causal loop diagrams (CLDs) of the urban mobility system were developed under two distinct scenarios: in its original state and after implementing shared micromobility, carsharing, ridesharing, and on-demand ride services. Beyond identifying key contributions from the literature, these CLDs were built by actively connecting variables and causal relationships across multiple studies, capturing systemic interdependencies that isolated, linear approaches cannot reveal. Results indicated that a non-linear paradigm of thinking provides a comprehensive framework to address urban mobility issues. Interpreting the CLDs from a sustainability perspective revealed that policies favoring one mode of transportation, without considering indirect and long-term effects, can undermine the sustainability of the system. Furthermore, the resulting qualitative models facilitate the visualization of both the direct and indirect consequences of implementing technologies and public policies.