Driving in a simulator and lower limb movement variability in elderly persons: can we infer something about pedal errors

Driving through an intersection requires observing and monitoring traffic conditions and the driving environment. It also requires, among other things, accurate right foot movements. It is with podal actions on brake and accelerator pedals that the driver controls the speed of the vehicle. Older adults exhibit greater motor variability than young adults [1, 2]. This increased variability may affect the accuracy of right foot movements while driving. It was hypothesized that, when stopping at an intersection, elderly drivers would show podal movements characterized by hesitation when moving from the accelerator to the brake pedal and by less stable temporal and spatial right foot movements than young drivers. Young (aged 21-42 years, n = 15) and older (aged 61-79 years, n = 25) active drivers participated. A driving simulator was used. Before the experimental session, all subjects drove an 8-km practice run to familiarize themselves with the simulator and the general feel of the pedals and steering. For the experimental run, all participants drove through the same 16-km route of a simulated neighbourhood (27 events consisting of crossings with a stop sign or crossing lights). For each event, the linear amplitude and within-subject variability of the right foot was calculated. The young adult generally released their foot from the accelerator pedal and moved toward the brake pedal without any hesitation. Elderly individuals showed more variable right foot movements (from the accelerator pedal to the brake pedal) characterized by the presence of several submovements (beyond small wobbling movements). Older drivers' right foot movements are more variable than that of young drivers. More research is needed to determine if there is a direct relationship between this lower limb movement variability, and serious pedal errors.