Characterizing Technology's Influence on Distractive Behavior at Signalized Intersections

Abstract

Distracted driving existed since the invention of the automobile; however, the emergence of the cell phone and electronic devices created another source of distraction that affected drivers visually, physically, cognitively, and audibly. Many studies investigated factors that influenced saturation flow and startup lost time at a signalized intersection, but the impact of new distractions, such as electronic devices and in-vehicle entertainment systems, remained less investigated. This study aimed to characterize technology's influence on driver behavior at intersections and the impact of distractions on startup lost time through a field test conducted at three intersections in Texas. This study used observational analysis and hypothesis testing to understand distraction behaviors and their impacts on individual and aggregated startup lost time. On average, 15% of drivers experienced distraction during a red indication, and a cell phone distracted more than 60% of these drivers. However, in vehicles located behind a heavy vehicle at an intersection, 20% of drivers were distracted, and 80% used a cell phone. Statistical analysis showed that distraction caused significantly higher headways and total lost times than non-distraction conditions. More importantly, technology-induced distraction, which created significant intersection delay, was more uncertain and varied from event to event more than non-technology-induced delay. This study showed that technology-induced distractions from the prevalent use of cell phones created an impact on startup lost time and saturation flow, which remained critical to properly determine the phase and cycle lengths.