Simultaneous interaction with in-vehicle systems while turning left: comparison among three groups of drivers

The growing introduction of new technologies inside vehicles represents a set of extra information sources. Its use can interfere with the driving activity and induce performance decrements. An on-road experiment was conducted to investigate how drivers reacted to the simultaneous interaction with in-vehicle systems. Forty-eight subjects (elderly, reference and novice) participated in the tests. They were asked to interact with one (road guidance system) or two (road guidance system and mobile phone) on-board devices. Their performance was evaluated for the turn left manoeuvres and main effects of system conditions were revealed. The simultaneous interaction with both in-vehicle systems induced participants to some performance decrements on the driving task: higher number of late activations of the turning indicator; lower mean speeds before the intersection; lower values of instant speed at the beginning of the turn manoeuvre; higher steering wheel variability; activations of the braking pedal with less pressure, later, and performing a higher number of strokes; and also less glances towards important areas of the environment. No significant difference was observed for the guidance task. The comparison between driver groups´ performance did not reveal enough significant differences in order to draw a general conclusion.