Claire Petit

Phoning while driving I: a review of epidemiological, psychological, behavioural and physiological studies

The impact of cell (mobile) phone use on driving performance has been widely questioned for 20 years. This paper reviews the literature to evaluate the extent to which phoning may impact behaviour with a risk to affect safety. After analysing epidemiological studies that give an overview of cell phone use, this paper examines the experimental results and focuses on variables showing that driving is impacted by holding a mobile-phone conversation. Information processing (e.g. reaction time and detection rate of cues related to driving information) and variables associated with vehicle control (e.g. lane-keeping, headway and vehicle speed) seem the most relevant. Although less studied than behavioural indices, physiological data give information about the supplementary potential strain that the driver may undergo under dual-task conditions. This first part of the review highlights common findings, questionable results and differences among studies, which originate from specific experimental designs with particular dependent variables, i.e. self-report, behavioural and physiological indicators. Finally, how drivers try to compensate for the additional load brought by phone use is described. Statement of Relevance: The two papers review the influence of mobile-phone use on driving performance. While there is ample evidence that this dual task is likely to increase the risk of car crash, the review analyses the variables eliciting detrimental conditions and, conversely, those that may preserve acceptable conditions for safety, close to usual driving. The decision of answering or initiating a cell phone call while driving depends upon the complex interaction among several variables, including driving conditions and drivers own characteristics. In addition, this decision remains under drivers awareness of being able or not to manage the two tasks simultaneously.

An integrated platform to assess driver's physiological and functional states

Physiological signals like Heart Rate, Respiration and Skin Resistance are relevant indicators to evaluate drivers mental state.

An integrated device to evaluate a driver's functional state

In the field of cognitive ergonomics, research on car drivers requires multimodal in-vehicle systems for recording not only driving-related behavior, but also contextual information from their surroundings. In addition, reliable information concerning a driver’s functional state should be obtained. In this article, we describe an integrated device simultaneously recording specific physiological data, video recordings of the driver and environment, parameters from the vehicle, and contextual data. Physiological signals from the autonomic nervous system provide objective and quantitative information on the driver’s alertness and his/her ability to process specific driving-related stimuli or other nonspecific information. Consequently, recorded physiological responses can be related to individual driving events. Electrodermal and cardiac activities are sensitive to time-dependent variations in arousal level and to certain external stimuli, so there is great interest in studying drivers’ behavior via measured physiological signals that have been established as suitable behavioral indicators. The present integrated device is capable of processing the relevant indices from raw measured data in real time.

Effects of Age and Task Load on Drivers’ Response Accuracy and Reaction Time When Responding to Traffic Lights

Due to population aging, elderly drivers represent an increasing proportion of car drivers. Yet, how aging alters sensorimotor functions and impacts driving safety remains poorly understood. This paper aimed at assessing to which extent elderly drivers are sensitive to various task loads and how this affects the reaction time (RT) in a driving context. Old and middle-aged people completed RT tasks which reproduced cognitive demands encountered while driving. Participants had to detect and respond to traffic lights or traffic light arrows as quickly as possible, under three experimental conditions of incremental difficulty. In both groups, we hypothesized that decision-making would be impacted by the number of cues to be processed. The first test was a simple measure of RT. The second and third tests were choice RT tasks requiring the processing of 3 and 5 cues, respectively. Responses were collected within a 2 s time-window. Otherwise, the trial was considered a no-response. In both groups, the data revealed that RT, error rate (incorrect answers), and no-response rate increased along with task difficulty. However, the middle-aged group outperformed the elderly group. The RT difference between the two groups increased drastically along with task difficulty. In the third test, the rate of no-response suggested that elderly drivers needed more than 2 s to process complex information and respond accurately. Both prolonged RT and increased no-response rate, especially for difficult tasks, might attest an impairment of cognitive abilities in relation to aging. Accordingly, casual driving conditions for young drivers may be particularly complex and stressful for elderly people who should thus be informed about the effects of normal aging upon driving.