Daryl Hibberd

Mitigating the effects of in-vehicle distractions through use of the Psychological Refractory Period paradigm

Modern driving involves frequent and potentially detrimental interactions with distracting in-vehicle tasks. Distraction has been shown to slow brake reaction time and decrease lateral and longitudinal vehicle control. It is likely that these negative effects will become more prevalent in the future as advances are made in the functionality, availability, and number of in-vehicle systems. This paper addresses this problem by considering ways to manage in-vehicle task presentation to mitigate their distracting effects. A driving simulator experiment using 48 participants was performed to investigate the existence of the Psychological Refractory Period in the driving context and its effect on braking performance. Drivers were exposed to lead vehicle braking events in isolation (single-task) and with a preceding surrogate in-vehicle task (dual-task). In dual-task scenarios, the time interval between the in-vehicle and braking tasks was manipulated. Brake reaction time increased when drivers were distracted. The in-vehicle task interfered with the performance of the braking task in a manner that was dependent on the interval between the two tasks, with slower reactions following a shorter inter-task interval. This is the Psychological Refractory Period effect. These results have implications for driver safety during in-vehicle distraction. The findings are used to develop recommendations regarding the timing of in-vehicle task presentation so as to reduce their potentially damaging effects on braking performance. In future, these guidelines could be incorporated into a driver workload management system to minimise the opportunity for a driver to be distracted from the ongoing driving task.

Lessons learnt from OS operations

This report focuses on the specific lessons learnt from the data collection in UDRIVE, derived from the difficulties encountered by the operation sites and the solutions applied to mitigate the problems where possible. These lessons learnt concern all aspects of the data collection. Such lessons learnt will provide useful insights for any future naturalistic driving study or field operational test. During the project, the operation sites provided three feedbacks related to their lessons learnt. These reports covered the pilot phase, the first six months of data collection and the last one at the end of the data collection. This iterative process gathered 71 lessons learnt. After the data collection, the final questionnaire was filled in by the participants and they provided with some interesting feedback. Most important lesssons learned were: Selecting only one or two vehicle types contributed to easier instrumentation of the Data Acquisaition System to the vehicles. However, this decision put some constraints in the recruitment of participants due the different fleet of vehicles across the European countries, especially some models were not very common in certain countries. One of the common problems across the Operation Sites (OS) was the participants’ drop-outs. The main lesson learnt was that it is important to maintain a set of replacement participants until the end of the project to cover any eventual drop out. Data protection was one of the most challenging aspects of the project. Dealing with images and personal data create some difficulties between the partners and their country data protection agencies. From the participants’ questionnaires, it was noted that even if they felt comfortable, their driving behaviour was somehow affected. Hide the equipment, and especially the cameras, the best it can be will help the participants drive normally. They also were pleased to have all the information beforehand and happy when dates, deadlines, incentives, etc., were respected as explained to them. When involving any external supplier (e.g. rental vehicle company, garage, equipment supplier, etc.). the role, responsibilities, response time, liability, etc., of every supplier have to be defined in more detail to avoid misunderstandings, delays or ambiguities. Developing as early as possible a very detailed and realistic plan of action allows to avoid delays, overspending, save resources and to achieve the project objectives.