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

Abstract

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.

How does decisional capacity evolve with normal cognitive aging: systematic review of the literature

“…Yet, when the speed of information processing is controlled in clinical research, the cognitive alterations previously described are significantly reduced [22,23,25,30,[33][34][35][36]. This is particularly true for tasks requiring mental flexibility, in which the decrease in processing speed is more prominent than difficulties in the analysis [25,33].…”

Driving Problems in the Elderly and Cognitively Impaired

“…Aging and Driving Driving represents a complex task during which the information from multiple sources needs to be processed. For example, information about other drivers, traffic lights, road signs, and car-specific and individual factors must be integrated, which poses an enormous challenge, especially to older drivers [1,2]. For younger people, driving is a highly automated process, but older drivers have to recruit additional cognitive resources due to the decreasing reliability of sensorimotor systems, which is known as "deautomation" [3].…”

“…With respect to cognitive function in the elderly, there is a great inter-individual variability, especially in executive functioning skills and attention, which sometimes complicates the differentiation between normal and pathological aging [4]. Recent data illustrate that reaction time, error rates, and no-response rates in drivingrelated tasks increase with normal aging and increasing difficulty of task conditions [1,15]. In studies that utilize on-the-road tests of situations with low or average cognitive load, older drivers perform as well as younger drivers [11,16].…”

Effects of aging on foot pedal responses to visual stimuli

“…It occurred 16 times more frequently in the older group and lasted 4.8 s on average. In a study of the aging effect on RT to traffic lights, Salvia et al [23] reported a similar phenomenon as no-response (> 2 s). They observed this phenomenon only in the older (> 70 years) group but not in the middle-aged group.…”

“…Although this function of PS-PVT seems unrealistic to driving situations, it may be useful for evaluating the ability to avoid serious accidents caused by unexpected runaway, given that the elderly drivers who caused such accidents often reported that they have been confident that the accelerator pedal is a brake pedal. Third, the cross-mode effect on RT is thought to be the Simon effect [25], which is known as a phenomenon that the RT of the reaction in the same direction as the stimuli is shorter than the RT to the reaction in the direction opposite to the stimuli [23]. This phenomenon can also be explained as the well-known effect of extending RT as task complexity increases.…”