Difficulties experienced by older drivers during their regular driving and their expectations towards Advanced Driving Aid Systems and vehicle automation

The aim of this study was to analyse the difficulties experienced by older drivers during their regular driving, and to identify their needs and their expectations regarding Advanced Driving Aid Systems (ADAS) and vehicle automation. More than 100 items were investigated by using a Focus Group method based on a Collective Questionnaire (named FoG-CoQS). Thirty elderly drivers, 15 females and 15 males aged from 70 to 81 years (mean age of 73.3; S.D. = 3.18) were recruited among a representative sample of 76 older drivers living in the Rhone area and having previously participated to an on-road experiment, in order to collect from this Focus Group method further information about the driving difficulties they experienced in their everyday life and their expectations towards driving aids. Seven main topics were more particularly investigated, recovering at last all the main dimensions of the driving task (from navigation to speed control, through intersection crossing). Regarding driving difficulties, one of the most interesting result collected is the high contrast between the literature review, identifying Left Turn (LT) manoeuvres at crossroads as a risky driving situation for elderly drivers, and the relatively low values of perceived difficulties (i.e. compared to other driving sub-tasks) collected during this Focus Group among our sample of older drivers. Regarding the driving aid functions investigated, 10 of them obtained high scores of "perceived utility" (i.e. overpassing 60% on scales ranging from 0% [no utility] to 100% [high utility]), and they concerned assistances liable to support all the main components of the driving task investigated in this study. Additional results are related to the differences between the elderly female and male drivers. Several driving situations were assessed as significantly more difficult to perform by the older female than by the older male drivers, like intersection crossing, entering expressways, or implementing a lane change manoeuver. By contrast, this gender effect is more limited regarding driving aids: synthetically, men and women have a positive attitude towards driving aid systems and their expectations for future ADAS are quite similar (for instance, "informative systems" are preferred than driving aids based on "vehicle automation"). Finally, from two transversal items (i.e. "difficulties" to perform a driving sub-task and "perceived utility" of ADAS), it was possible to rank older drivers' difficulties experienced during their everyday life (from lowest difficulties to "navigate on a familiar itinerary" to highest when "interacting with bicyclists") and their expectations towards driving aids (from lowest utility score given to "Automatic Lane Change systems" to highest utility value provided to "Speed Informer systems"). At last, older drivers' acceptance and expectations towards highly automated cars was also investigated: full automation was assessed as an interesting solution to ensure the self-mobility of elderly peoples in their circle, but also for themselves in the future, in case of impairments of their own cognitive or physical capacities. (C) 2017 Elsevier Ltd. All rights reserved.