Author(s):
Johan Engström, Mikael Ljung Aust, Matias Viström

Year of publication:
2010

Published in:
"Human Factors: The Journal of the Human Factors and Ergonomics Society", 52 ( 5 ) p. 551-559

Publication type:
Scientific journal article - peer reviewed

Abstract:
OBJECTIVE: The objective of the present study was to examine the effect of working memory load on drivers' responses to a suddenly braking lead vehicle and whether this effect (if any) is moderated by repeated scenario exposure. Background: Several experimental studies have found delayed braking responses to lead vehicle braking events during concurrent performance of nonvisual, working memory-loading tasks, such as hands-free phone conversation. However, the common use of repeated, and hence somewhat expected, braking events may undermine the generalizability of these results to naturalistic, unexpected, emergency braking scenarios. Method: A critical lead vehicle braking scenario was implemented in a fixed-based simulator. The effects of working memory load and repeated scenario exposure on braking performance were examined. Results: Brake response time was decomposed into accelerator pedal release time and accelerator-to-brake pedal movement time. Accelerator pedal release times were strongly reduced with repeated scenario exposure and were delayed by working memory load with a small but significant amount (178 ms). The two factors did not interact. There were no effects on accelerator-to-brake pedal movement time. Conclusion:The results suggest that effects of working memory load on response performance obtained from repeated critical lead vehicle braking scenarios may be validly generalized to real world unexpected events. Application: The results have important implications for the interpretation of braking performance in experimental settings, in particular in the context of safety-related evaluation of in-vehicle information and communication technologies.

More information / Full text:
http://publications.lib.chalmers.se/cpl/record/index.xsql?pubid=134764

Research area:
Traffic Safety Analysis

Project:
FICA 2 - Factors Influencing the Causation of Accidents and Incidents
(associated project)