Effects of auditory distractions on driving behavior during lane change course negotiation: estimation of spare mental capacity as a index of attention distraction

This study proposes a procedure to quantitatively estimate auditory distractions that are not accompanied by any visual diversions to clarify the influence of non-visual distractions on driving. In a laboratory experiment, spare mental capacities (measured in bits/s) for three arithmetic tasks were estimated for each subject driver, using the functional relation between the reaction time and the number of alternatives in choice reaction tasks using a subsidiary task method. The spare capacities obtained correlated significantly with the measures of speed control and physiological load during a lane change course negotiation on a test field. We observed that the driving ability deteriorated when the capacity decreased to less than 6 or 7 bits/s. Keywords: Driver distraction;