Passengers’ comfort in horizontal curves on mountain roads: a field study using lateral accelerations

Abstract

The comfort of passengers is one of the most significant advances in modern passenger transport. Despite its subjectivity, it could be related to the lateral accelerations on horizontal curves. This study aimed to analyze the relationship between passengers' comfort and lateral acceleration in two-lane rural mountain roads. Real-vehicle experiments were performed with 58 passengers on one road in the Ecuadorian Andes. They explored the influence of age, sex, level of stress, level of physical pain, speed, and lateral acceleration on passenger comfort. Two instruments were employed to collect data: a survey conducted to the passengers and a precise GPS device. In the survey, the passengers selected their comfort or discomfort within the curve. The GPS collected the vehicle speed, lateral accelerations and, its trajectory. As a result, it calibrated two models using Structural Equation Modeling (SEM) with the factors: comfort values, stress level and lateral acceleration. Besides, it calibrated six models using linear regression with several thresholds of speed. Differences were found between right and left curves, which had not been detected by previous researchers. The research suggests thresholds of lateral acceleration in mountain roads in a Latin American country that would improve their design for better performance and safety.