Effect of Driver Cell Phone Use on Queue Discharge Patterns at Signalized Intersections

Abstract

Queue discharge patterns and driver cell phone use were monitored and analyzed at four intersections in Charlotte, North Carolina. Of the more than 3,700 drivers observed, about 13.3% were talking on a cell phone and approximately 1.8% were texting while driving. The saturation headways and start-up lost times of queues containing cell phone users were compared with queues lacking the presence of cell phone users. Results show that although text messaging has a clear negative effect on discharge patterns, talking on a cell phone has an insignificant effect. Secondary analyses imply that drivers talking on a cell phone have a stabilizing effect because they likely perform worse than attentive drivers but much better than those engaged in a visually demanding distraction. Findings also show that the performance of drivers talking on a cell phone is fairly consistent, whereas the performance of nonusers is inconsistent because of myriad other distractions with widely varying effects on driver abilities. The performance of texting drivers was found to be the most variable, perhaps because of the sporadic, often intense visual demands associated with texting while driving.