Driving in a simulator versus on-road : the effect of increased mental effort while driving on real roads and a driving simulator

Abstract

The objective of this thesis is to study human response to increased workload while driving in a driving simulator compared to real world behavior. Driving simulators are a powerful research tool, providing nearly complete control over experimental conditions-- an ideal environment to quantify and study human behavior. However, participants are known to behave differently in a driving simulator than in an actual real-world scenario. The same participants completed both on-road and virtual drives of the same degree of roadway complexity, with and without a secondary task conditions. Data were collected to describe how the participants' vehicle-handling, gaze performance and physiological reactions changed relative to increases in mental workload. Relationships between physiology and performance identified physiological, performance, and gaze-related metrics that can show significant effects of driving complexity, environment, and task. Additionally, this thesis explores the inadequacy of multinomial predictive models between the simulator and instrumented vehicle. Relative validity is established in the performance-physiology relationship for on- and off-road fixation frequencies, but few correlations between the simulator and instrumented vehicle are apparent as mental workload increases. These findings can be applied to the real world by providing specific variables that are adequate proxies to detect changes in driver mental workload in on-road driving situations; valuable for in-vehicle driver assistance system research. Overall, the simulator was a suitable proxy to detect differences in mental workload in driving task; and initial steps have been taken to establish validity, and to supplement on-road driving research in these high-demand driving scenarios.