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Bianchi Piccinini G.F.,University of Porto | Rodrigues C.M.,University of Porto | Leitao M.,Polytechnic Institute of Porto | Simoes A.,CIGEST
Journal of Safety Research | Year: 2014

Problem The Adaptive Cruise Control is an Advanced Driver Assistance System (ADAS) that allows maintaining given headway and speed, according to settings pre-defined by the users. Despite the potential benefits associated to the utilization of ACC, previous studies warned against negative behavioral adaptations that might occur while driving with the system activated. Unfortunately, up to now, there are no unanimous results about the effects induced by the usage of ACC on speed and time headway to the vehicle in front. Also, few studies were performed including actual users of ACC among the subjects. Objectives This research aimed to investigate the effect of the experience gained with ACC on speed and time headway for a group of users of the system. In addition, it explored the impact of ACC usage on speed and time headway for ACC users and regular drivers. Method A matched sample driving simulator study was planned as a two-way (2 × 2) repeated measures mixed design, with the experience with ACC as between-subjects factor and the driving condition (with ACC and manually) as within-subjects factor. Results The results show that the usage of ACC brought a small but not significant reduction of speed and, especially, the maintenance of safer time headways, being the latter result greater for ACC users, probably as a consequence of their experience in using the system. Summary The usage of ACC did not cause any negative behavioral adaptations to the system regarding speed and time headway. Practical applications Based on this research work, the Adaptive Cruise Control showed the potential to improve road safety for what concerns the speed and the time headway maintained by the drivers. The speed of the surrounding traffic and the minimum time headway settable through the ACC seem to have an important effect on the road safety improvement achievable with the system. © 2014 Elsevier Ltd.

Bianchi Piccinini G.F.,Chalmers University of Technology | Rodrigues C.M.,University of Porto | Leitao M.,Polytechnic Institute of Porto | Simoes A.,CIGEST
Safety Science | Year: 2014

Adaptive Cruise Control (ACC) is a system that maintains driver-selected speed and headway to a preceding vehicle. The system presents some limitations that are, in part or totally, unknown to the users. Hence, many drivers exhibit a rudimentary mental model of the system and place excessive trust in the device. As a consequence, negative effects on road safety can easily occur. However, to date, many studies conducted on ACC have comprised participants who had never used ACC previously. Therefore, there is limited knowledge of how ACC affects the driving performance of experienced users of the system. To shed light on this point, twenty-six participants, divided into two groups (ACC users and non-users) drove twice in the simulated environment (once with the ACC and once manually). During both drives, the participants experienced a critical situation (stationary vehicle stopped in the cruising lane of the highway). The results show that negative behavioural adaptations to the ACC resulted from the usage of the system with regard to the critical situation: the risk of collision during the driving with ACC was increased compared with the manual driving for both groups of drivers. Besides, the research stresses the negative large correlation between the driver's mental model of ACC operation in the critical situation and the safety margins maintained by the ACC users during the same situation. Finally, it was found that the drivers' trust in the system does not have an influence on the drivers' behaviour during the trial with the ACC. © 2014 Elsevier Ltd.

Ferreira A.L.,CIGEST | Rola S.,CIGEST | Simoes A.,CIGEST
IET Intelligent Transport Systems | Year: 2013

It has already been proved that the use of the mobile phone while driving has a negative impact on the driving performance, increasing the risk of being involved in a car accident. However, in order to plan adequate corrective actions, there is the need to know more about people's usage of mobile phone while driving and what are drivers' opinions about the risk represented by that action. The aim of the present study was three-fold: to investigate the patterns of use of the mobile phone while driving by gender and age, to find out the prevalence of hands-free systems use by gender and age and, finally, to understand the perceived hazard in using the mobile phone while driving by gender and age. A sample of 769 Portuguese drivers answered a web-based survey developed in the frame of the European project INTERACTION. The answers revealed that the rate of mobile phone use among Portuguese drivers is very high. In addition, results showed that drivers perceived talking on a hands-free mobile phone while driving as much less dangerous compared with speaking on a hand-held mobile phone. Based on those results, further research is suggested. © The Institution of Engineering and Technology 2013.

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