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Author ORCID Identifier



Open Access Dissertation

Document Type


Degree Name

Doctor of Philosophy (PhD)

Degree Program

Industrial Engineering & Operations Research

Year Degree Awarded


Month Degree Awarded


First Advisor

Donald L. Fisher

Second Advisor

Matthew R.E. Romoser

Third Advisor

Michael Knodler Jr.

Subject Categories

Operations Research, Systems Engineering and Industrial Engineering | Other Operations Research, Systems Engineering and Industrial Engineering


Distractions have long been associated with crashes. A review of the literature shows drivers engaging in secondary tasks to be three times as likely to crash as compared to attentive drivers. Although several studies report that excessively long glances away from the forward roadway elevate the risk of crashes, little research has been conducted to determine how long a driver needs to glance towards the forward roadway in between glances inside the vehicle to perform a secondary task in order to detect threats present in or emerging from the forward roadway. To determine this, drivers were asked to perform simulated in-vehicle tasks requiring glances alternating inside and outside the vehicle. The glance inside was limited to 2 s. The glance outside was varied between 1 and 4 s. Eighty five participants were evaluated across two experiments involving one continuous view and three alternating view (baseline, low load and high load) conditions. Drivers in all alternating conditions were found to detect far more hazards when the forward roadway duration between two in-vehicle glances was the longest (4 s). The decrease in hazard detection at the shorter roadway durations was a combined consequence of the drivers having to devote more resources to their driving (swapping), and having to switch their attention between the primary (driving) and secondary (in-vehicle) tasks (switching). There was an additional carry over effect of load observed in the alternating high load condition when drivers were loaded even while looking at the forward roadway (spillover). There was an effect of type of processing (bottom up versus top down) and eccentricity (central versus peripheral). The asymptotic estimation of the threshold duration indicated that the drivers’ minimum glance duration on the forward roadway be at least 4 seconds when engaged with an in-vehicle task that elicits swapping effects and at least 7 seconds when engaged with an in-vehicle task eliciting switching effects.