An Acoustic Monitoring System for Improving Passenger Experience in Public Transport

The quality of the travel experience on public transportation is a key element in user satisfaction and mode choice. Among the various factors, the onboard acoustic environment plays a significant role, particularly in relation to social noise generated by passengers. This paper presents an acoustic monitoring system based on the principles of nudge theory, designed to improve travel experience through non-invasive behavioral interventions. The proposed solution consists of sensing nodes equipped with digital microphones and microcontrollers, capable of detecting sound levels and transmitting data in real time. A visual feedback interface, based on a multi-level color scale, provides passengers with an immediate representation of acoustic conditions, encouraging more mindful behavior without imposing constraints. The system was experimentally validated on a public bus under real operating conditions. Results show a baseline acoustic condition of approximately 75 dB, associated with vehicle operation, while passenger-generated noise produces significant increases, with typical values ranging from 80 to 100 dB and peaks exceeding 110 dB in high-interaction scenarios. These findings demonstrate the system’s ability to distinguish between mechanical and socio-relational noise components. Overall, the proposed approach represents a low-cost, scalable, and easily deployable solution for improving acoustic comfort and enhancing the travel experience in public transportation systems.