Strategies often proposed to combat the growing traffic congestion problems of urban environments target enhancements to increase the use of bus transit. Therefore, service providers are keen to identify and understand factors that could attract more transit riders. Other than affordability, most researchers explored convenience and stress factors such as schedule uncertainty, waiting time, travel time, crowding, noises, and smells. However, few studies evaluated the significance of ride quality. The high cost to collect and analyze roughness data likely deters such studies. This work developed a low-cost smartphone based method and associated data transforms to characterize ride quality for non-uniform speed profiles. The method distinguished between vibrations induced from road unevenness and operator behavior. The authors validated the accuracy of the method by conducting surveys to characterize the perceived roughness intensities from buses traveling routes of distinctly different roughness levels. The surveys found that smooth rides mattered to most passengers, and that rough rides could even lead to some loss of ridership. Additionally, the authors proposed a theory of roughness acclimation and provided some evidence that unlike objective measurements, subjective assessments of ride quality could lead to significant biases and inconsistencies.
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