Consistency and sensitivity of lane change test according to driving simulator characteristics

The aim, here, is to evaluate consistency and sensitivity of the lane change test (LCT), which is the subject of a proposed ISO standard. The method is intended to estimate driver distraction while a secondary task is being performed, by measuring performance degradation on a primary driving-like task. An experiment was conducted in two experimental contexts: a fixed-base driving simulator and a personal computer (PC) (including pedals and steering wheel), and with two auditory and two visual-manual secondary tasks. Three performance measures were calculated: adapted mean deviation, correct lane change (LC) ratio and mean delay in LC initiation. The effect of experimental context was significant. The trajectory, measured by the adapted mean deviation, was significantly better on the simulator and the percentage of correct LC higher. This difference might be explained by the greater immersion of the driver in the driving scene, which led to easier control of the trajectory in the simulator. Conversely, participants initiated quicker responses to signs when using the PC, to the detriment of trajectory control. The LCT was also proved to be sensitive enough to evaluate driving performance impairment because of the simultaneous performance of secondary tasks, even if it failed to differentiate all of them.