Evaluating the cycling comfort on urban roads based on cyclists' perception of vibration

Abstract

Attainment of cycling comfort on urban roads encourages people to use bicycles more frequently, which has social and environmental benefits such as to improve air quality, alleviate congestion and reduce carbon emissions. Vibration is perceived by cyclists as one of the most important indicators of cycling comfort, and it greatly influences people's choice of bicycles. However, a comprehensive correlation between cyclists' perception of comfort and cycling vibration has not yet been established in the current knowledge. In this study, a total of 46 sections of 24 urban roads (approximately 11,500m in length of asphalt pavements) in the city of Xi'an, China, were selected for field test. An innovative Dynamic Cycling Comfort (DCC) measure system consisting of an accelerometer, GPS logger and smart phone, was installed on the hand bar of a shared bicycle typically used in Xi'an, to record the dynamic data of vibration, trail, speed and mileage. Reliability of the DCC was verified, and the effect of test conditions (speed, bicycle type) on vibration evaluated. The vibration data were processed in accordance with ISO 2631 to quantitatively characterize the vibration level on each tested section. Furthermore, a total of 17 volunteers participated in this test, and the cyclists' perception of vibration in each section was obtained via a purpose-designed questionnaire. The volunteers' perception of environmental factors such as scenery, weather, road geometry, congestion and traffic condition were summarized to evaluate the influencing factors for cycling comfort. The thresholds of acceptable rate, comfort level and vibration perceptible level were established, based on the correlation between cycling vibration awv and subjective perception described in the questionnaire. In addition, the cycling comfort on the asphalt pavements (3521 m) within Qujiangchi Park was mapped, to demonstrate the practical use of this study. Results showed that the DCC is able to capture the cycling data timely and accurately. K-means clustering analysis showed that the cycling vibration increases with the increase of cycling speed. Meantime, a heavier shared bicycle with solid tires results in higher cycling vibration compared with a lighter one with inflatable tires. In addition, the comfort level is proportional to acceptable rate, and inversely proportional to vibration perceptible level. The cycling comfort mapping for Qujiangchi Park proved that there is great potential to use the vibration (comfort) data to monitor pavement surface quality and for cyclists to determine their desirable cycling route. Results of this study should be interested by cyclists, bicycle manufacturers, transport planners and road authorities.