The purpose of this Australian simulator study was to investigate the relationship between self-regulatory secondary task performance, such as mobile phone use, and driving. To conduct this study, thirty-five participants aged 18-29 years completed a series of three simulator conditions. These conditions included a non-distraction condition, driving while using a mobile phone for hands-free conversation, and driving while performing a visual-manual interaction (i.e., texting) task on the mobile phone. Each trip contained three road traffic conditions commonly found on Australian roads: straight driving in a suburban setting with a speed limit of 80 kph, s-curve in a suburban setting with a speed limit of 80 kph, and two-lane motorway driving with a speed limit of 110 kph. Trips were 10km in length and took approximately 15 minutes to complete.
Results showed that the level of engagement in the secondary task influenced both the longitudinal and lateral control of the vehicle. For example, drivers who performed multiple hands-free interactions typically drove at a lower speed. In contrast, drivers who performed longer texting interactions drove at a higher speed. Furthermore, the difficulty of the drive (i.e., straight or s-curve) influenced the performance level in both the hands-free and texting phone tasks. This finding suggests that road curves increase the driver’s workload as it requires cognitive, physical, and visual focus.
Oviedo-Trespalacios, Oscar & Haque, Md. Mazharul & King, Mark & Washington, Simon. (2017). A New Model for Human Behavioural Adaptation in Distracted Driving.