Measurement and analysis of acoustic phenomena occurring in public transport buses based on surveys and field study

The article presents results and analysis of noise measurements in passenger compartments of public transport buses. Ten Solaris Urbino 12 m buses were selected for performing the measurements, including five buses with an automatic 4-speed transmission and five with a 6-speed transmission. The research related to the assessment of the acoustic climate in buses was conducted in two stages: in the first stage surveys were carried out, which were then followed by field study in the second stage. The aim of the performed research was to identify places inside the bus with potentially high sound levels and then a real assessment of the noise affecting passengers. The survey aimed at the assessment of vibroacoustic comfort in buses while driving. The questions answered by the respondents concerned places inside the vehicle and vehicle movement phases, during which noise and vibration are the strongest. Additionally, the respondents made a subjective assessment of noise and vibration inside the bus while driving. The filed study was conducted with 10 measuring microphones placed in the passenger compartment of the bus and consisted in simultaneous recording of sound levels and the speed at which the bus moved. The study was carried out at a standstill and while driving. The conducted measurements allowed the identification of the highest and lowest sound levels in the vehicle at a standstill and while driving.