Measuring Bus Comfort Levels by using Acceleration Instantaneous Values

Comfort on board of a bus service plays an essential role in the levels of satisfaction perceived by bus passengers; therefore, comfort improvement can be a convenient strategy for attracting more customers. Kinematic parameters, especially accelerations, significantly affect passenger comfort. For this reasons, the aim of this paper is to study perceived comfort on board, based on the accelerations recorded along paths covered by buses. The experimental study involves two lines connecting the city of Cosenza with the University of Calabria, sited in the southern Italy.In order to find a measure of comfort, two items are needed: interviews to passengers (subjective data) and kinematic parameters (objective data). For the collection of subjective data a questionnaire was appropriately designed and addressed to a sample of university students, while a smartphone, equipped with GPS device and 3-axis accelerometer was used to record the accelerations. A specific app allowed the acceleration values (longitudinal, lateral and vertical accelerations) and speed values to be recorded, by adopting a frequency of 1 herz, together with the instantaneous bus position (latitude and longitude), along the trajectory followed during the trip.Based on the parameters recorded, we determined the thresholds of some kinematic quantities and developed two comfort indices that provide an aggregate comfort judgement associated with each run. In addition, we can know at what points of the track the quantities calculated are below or above the threshold value, being the recorded data instantaneous and geo-referenced values.