Drivers’ acceptance of adaptive warning–monitoring systems. Findings from a car driving simulator study

Private vehicles are nowadays often equipped with advanced driver assistance systems (ADAS) that aim to assist drivers in maintaining safe driving behavior. Understanding users’ acceptance and perceptions towards them is therefore crucial, mostly before developing or implementing additional assistance features. Driving simulators provide a unique opportunity to test ADAS in a controlled environment, in particular when safety–critical situations need to be replicated in a way that is not possible on real roads. In this study, an advanced warning–monitoring system, developed in the context of the recent European–wide naturalistic driving study (i–DREAMS¹), is implemented in a driving simulator environment, so that is tested before it is then deployed in vehicles on real roads. For this purpose, a driving simulator study was conducted in Germany, in which 60 drivers participated. The study included three drives: the first was a baseline drive in which in–vehicle warnings were not activated, the second included real–time warnings (interventions), and the third had an additional distraction component, introduced by means of a mobile phone texting task (imposed on participants). Drivers were also asked to fill various questionnaires focusing on their perceptions towards general ADAS and driving, but also towards the implemented system (the i–DREAMS system²). A statistical analysis of the questionnaire results led to the partial validation of the technology acceptance model (TAM) for the i–DREAMS system, for which perceived usefulness (PU) and perceived ease of use (PEU) of the system, both of which resulted from a factor analysis of the attitudinal questions, were found to be crucial factors for the behavioral intention to use it. In the validated TAM, PU of the i–DREAMS system was found to be positively impacted by external variables, namely PU of similar ADAS systems, whereas PEU was found to be positively influenced by driving experience. While the system was overall positively received, findings and lessons learned from the experiment were transferred to future field experiments conducted within the same project, and suggested more generally that driving simulator studies could be very beneficial for testing newly developed in–vehicle technologies, leading on the long run to safer roads.