G.E. Burnett, R.A. Donkor
Head-up Displays (HUDs) aim to provide the driver with salient visual information that is readily available in their line of sight and can be accessed rapidly with minimal visual accommodation. However, concern has been raised about whether complex HUD information can cause attention capture reducing a driver’s ability to rapidly and correctly detect critical road events (especially those in the periphery). An experiment was conducted in a fixed-based simulator to measure the effects of HUD information complexity on driver behaviour and performance. Eighteen experienced drivers were requested to follow a lead vehicle along a motorway and perform a range of secondary tasks using a HUD (e.g. what is the current vehicle speed). These tasks varied in complexity, based primarily on the number of HUD symbols to search through. In addition, participants were also asked to respond to Peripheral Detection Tasks (PDTs) using steering wheel controls. At times, these PDTs would occur simultaneously with HUD presentation. Results showed there was a significant increase in PDT response times and reduction in PDT response accuracy as the number of symbols on the HUDs increased. The clearest negative change arose when progressing from four to seven symbols on the HUD. Moreover, lane-keeping ability significantly deteriorated with increasing HUD complexity. Based on these results, it is recommended that HUDs should ideally have no more than four distinct symbols, but may include five or six symbols depending on other design factors.
Keywords: Head-Up Displays; distraction; user-interface; vehicles; driving simulation; human factors