Drivers’ Perceived Sensitivity to Crosswinds and to Low-Frequency Aerodynamic Lift Fluctuations

The automotive industry continues to increase the utilization of computer-aided engineering. This put demands on finding reliable objective measures that correlate to subjective driver assessments on driving stability performance. However, the drivers’ subjective perception of driving stability can be difficult to quantify objectively, especially on test tracks where the wind conditions cannot be controlled. The advancement in driving simulator technology may enable evaluation of driving stability with high repeatability. The purpose of this study is to correlate the subjective assessment of driving stability to reliable objective measures and to evaluate the usefulness of a driving simulator for the subjective assessment. Two different driver clinic studies were performed in a state-of-the-art driving simulator. The first study included 38 drivers (professional, experienced and common drivers) and focused on crosswind gust sensitivity. The second study focused on straight-line driving stability at constant crosswinds, where the influence of unsteady aerodynamic wake fluctuations was assessed. This study involved three of these professional drivers. It was found that the subjective assessment of crosswind sensitivity can be correlated with the sensory motion response of the vehicle (lateral acceleration and yaw velocity), and also with vehicle path curvature (visual feedback). The assessment of fluctuating CFD loads showed that blind-tested professional drivers could differentiate vehicle configurations in agreement with their on-road subjective ratings. Based on the results of this study, a new aerodynamic lift target for high speed straight-line stability, which also accounts for the fluctuating loads of the wake, is proposed.