Assessing Driver Distraction from Cell Phone Use

Abstract

The relative driving performance of 37 drivers was compared in a controlled laboratory environment to assess how cell phone use affects driver performance on urban arterials and local roads. The stimulus consisted of answering a call on a hand-held cell phone and engaging in a scripted conversation with study researchers. A driving simulator replicated various typical real-world driving environments and roadway situations. Subjects drove a control scenario (baseline condition) and a test scenario in which they were asked to answer a set of questions using a hand-held cell phone while driving. The subjects were required to navigate various conditions, such as respond to traffic signs and signals, negotiate vehicular traffic when turning, and yield to unexpected pedestrians and bicyclists. Driver performance was assessed for overall driver performance scores, speed profiles, vehicular lateral placement within travel lanes, and number of crashes that occurred during the simulator experiment. Changes in measures between control and test scenarios were subjected to a series of statistical tests. Analysis results indicated that when cell phones were used while driving, subject performance scores were significantly lower, average speeds significantly slower, and proportions of improper lateral placement observed significantly higher. In addition, twice as many crashes (also statistically significant) were observed when subjects used cell phones while driving as were observed under the control condition. In this controlled laboratory experiment, the distraction caused by answering a call and engaging in a conversation on a hand-held cell phone significantly degraded driving performance.