New Transverse Unevenness Indexes of the Road Profile

Abstract

The influence of the transverse unevenness indexes of the road profile on the vehicle vibration was rarely studied in the past. This study proposes new road indexes of the transverse road profile and their correlation with the whole-body vibration (WBV) measured on the passenger’s and the driver’s seats in a passenger car. The proposed new indexes are the range, interquartile range, and standard deviation of the transverse profile vertical displacements. The benchmark was the maximum rut depth specified in the European standard. The WBV was evaluated on the passenger’s and driver’s seat surface in three perpendicular axes of various vehicle types traveling on test sections of different categories and quality over 4,100 km. The correlation of the proposed indexes with the total passenger’s seat acceleration was similar to that for the maximum rut depth. Using the combination of longitudinal and the proposed transverse unevenness indexes improved the correlation with the passenger’s seat vibration in the lateral direction by 23% and the model RMS error (RMSE) decreased by ∼15% compared with that of the maximum rut depth.