To preserve the independence and quality of life of our seniors, it is essential to reconcile the requirements of security issues with mobility ones. Public action in road safety can be renewed by being sensitized to the issue of security management, i.e. by searching underlying rationalities from the observed behaviors. This requires studying the security in action from senior drivers' activity analysis. Most of the older drivers use their capabilities in order to build an appropriate response to the driving conditions encountered. These coping skills enable them to remain fit to drive. Starting from practice, this approach allows to redefine the "good driving" rules and thus shed new light on the driving assessment issue. In French, the translation of the word 'driving' is a polysemic term. In this 'habilitation to conduct research' dissertation, it will is used in its generic sense. It includes an objectified part (behavior) and a non-objectified part: the reason, the motive, the act(s) of thought that come before, during or after a performance. The research works I have conducted tried to elucidate the roles of cognitive, affective and conative processes to capture the processes' intermediate parts (or links) involved in the adopted behaviors; we based our investigations on the study of intra and inter-subjective processes. This approach allows us to objectivize the origins and sometimes the causes of behaviors. However, to better understand them, an observation approach must be associated. Indeed, through observation, the objective reasons to act are figured-out by building a posteriori arguments based on observed behavior and statements from the individuals. These two approaches are complementary, they allow to explain and to understand behaviors in order, ultimately, to better act. A central concept in the study of adaptation to normal cognitive aging is the cognitive control (ability to respond to stimuli based on the present context, past indices and internal aims). The study of cognitive control during driving allows the description of different forms of adaptation exploring their dimensions, their mechanisms and their determinants. To understand seniors' behaviors, it is also necessary to take into account their situation, their needs, their physical and social environments to better describe their difficulties and the risks they are exposed to. The complementarity of different tools and methods used to tackle this issue is addressed. The research conducted to date help to clarify aims to be reached in order to increase senior safety, to identify priority actions and also to help public authorities to take rational decisions that maximize both the mobility and safety of older drivers. Through examples, we described the adaptive strategies adopted by some older drivers to safe act against disturbances that appear while aging and we also describe how we can identify older drivers who do not adapt optimally. As attention capacities are essential to preserve a safe driving, an expand section on attentional failure while driving is also presented. Within the two research lines, whose main results are detailed below, it is shown that the concept of estimation bias is central to the implementation of driver' behavioral self-regulation. 1. Older drivers' self-regulatory behaviors were explored regarding declared aberrant driving behaviors and perceived abilities . The study suggests that perceived abilities, especially self-assessed driving related processing speed and attentional abilities, play a major role in the decision to self-regulate its own behaviors (avoiding difficult driving situations) and that such self-efficacy beliefs are a stronger predictors of avoidance than driver behavior questionnaire. The avoidance of difficult driving situations as a behavioral self-regulation option were also compared between young and older drivers : the older drivers reported greater avoidance situations than the younger drivers, more significant correlations were observed between self-reported driving avoidance and both health-related perceptions and objective indicators of cognitive function among them. To explore if older adults spontaneously draw on their monitoring skills to accurately self-regulate their behaviors, we explored drivers' self-regulation within discrepancy reduction framework and the region of proximal learning : we have shown that younger and older drivers were thus equally able to identify their region of proximal learning. In a complementary study, we have also shown that exposing older drivers to a stereotype threat severely impairs their self-regulatory skills; this is at least partly due to exhaustion of the executive resources appearing through working memory overload . These research works were the starting point for a wider reflection on the implementation of more effective training interventions, especially for older drivers that present a cognitive self-assessment bias . These interventions will allow to support behavior change in order to improve the comfort and safety of older drivers. 2. Due to substantial gains in road safety due to speed reduction, safety-belt wear, and the diminution of driving under alcohol influence, the proportion of accidents due to attention failure while driving increases. In a four years project funded by the French research agency (ANR), we worked in a multidisciplinary team (cognitive and mathematical sciences and epidemiology) to clarify the road safety issues and identify avenues for innovative actions to better supervise the driver. A first step was to identify the risk fractions attributable to different types of attention failure in order to better prevent them. A survey was conducted in Bordeaux hospitals. 955 drivers injured in a road accident were interviewed following their admission to the emergency rooms. They were asked to report their activity and the content and intensity of their thoughts in the moments before the accident. Of the 453 drivers related to mind wandering (MW), the contents proved intense or disturbing for 121. These thoughts were significantly more frequent among drivers responsible for the accident. It thus appears that an accident on ten is linked with a driver intrusive thought (Galéra et al., 2012) . Distractions related to events outside the vehicle and driver activity are also associated with responsibility (OR 3.3 and 9.6 respectively). Attributable share of casualties related to external distraction is estimated at 9 % (Bakiri et al., 2013) . These epidemiological findings show that attention failure during driving is a road safety deposit that may reduce the number of casualties on our roads. In a second step, we also tried to understand the influence of various failure of attention on driver behavior. First, three forms of cognitive interference were studied to describe their effects on simulated driving behavior and the treatment of information (studied with the evoked potentials technic). Visuospatial cognitive distractions impacted anticipation (by observing the contingent negative variation, CNV), while verbal distractions impacted the information processing at sensory and cognitive processing steps. The experimental results showed the differential influences of various types of cognitive control (attentional control, emotional control and behavioral inhibition). Experiments conducted on a simulator and on the road showed that: retrospective and prospective thoughts change ocular strategies (eye gaze and increased pupillary diameter; Lemercier et al., 2014) , the increased cognitive effort results in increased heart rate associated with a decrease of its variability and different regulation strategies have been described for the control of cognitive effort while driving (Gabaude et al., 2012) . A complementary study have then shown that the real-time detection of cognitive effort is feasible . A survey through the use of an off-line questionnaire was also conducted to reveal the individual and contextual characteristics of driving in a MW state, to describe behavioral consequences of MW on driving and to determine the characteristics of off-task thoughts while driving (Berthié et al., 2015) . In this research project, the influences of MW on the accident risk and on the driving behavior have been demonstrated, it provides avenues of research and an insight into new original development. The complementarity of the two types of methods to analyze the impact of cognitive distraction on driving activity by exploratory and confirmatory analysis was discussed. Geometry information methods have been used to analyze data applied from the vehicle side to enable the thresholds identification beyond which it is probable that the driver performs driving competing activity (Letelier, 2012) . These criteria are not always sensitive because of the variability of observed behaviors. The psycho-ergonomic analysis of the drivers' activities could help to better describe the various regulation strategies that can be adopted. This approach is required to identify, from the data side, the most sensitive and specific algorithms. This will be the first step towards the development of a driver supervision system, thus contributing to the objectives of reducing road accidents. By comparing different disciplinary perspectives, this project has allowed substantial progress on the subject of attention failure while driving. We began to understand the causes and origins of various attention failure and their consequences on driving. The exploratory analysis of sequential data and supervised learning techniques (data-mining) applied to the data collected on highway are used to search algorithms able to identify a distracted driver. New technological challenges, consisting in the adaptation of driving assistance depending on the driver state, will soon be addressed. The work presented in this dissertation also stress the need to broach health issues in their complexity and not to address the driving ability issue in regard of a unique road safety policy. To take advantage of successful aging, the elderly must evolve with their environment and adapt consequently. The increase of knowledge on this adaptation notion is essential. The knowledge gained on the adaptation to cognitive aging must now be exploited to develop interventions to accompany the older drivers in various stages of adoption of precautionary behavior. In the perspective section outlined in this dissertation, we develop four directions to implement research actions in order to: accompany the public authorities on issues related to the safe mobility of seniors, better prevent negative effects of aging, offer to older users the digital revolution opportunities taking place in the health and transportation domains and lastly to promote a continuum of mobility for our seniors. In future research, it will also be necessary to evaluate the effectiveness of the different actions or interventions proposed, some first ideas in this direction are suggested.