Evaluation of Driver Performance and Distraction during use of in-vehicle Signing Information

Abstract

The goal of this study was to examine the in-vehicle signing (IVS) function displayed on a mobile device to determine whether drivers’ compliance with speed limits increased when IVS information was present. The study also sought to identify whether any visual distraction occurred while the IVS information was being used. Notifications of speed zone changes along a roadway, of school zones, construction zones, and curves were visually displayed on a mobile device as per project requirements. Sixty participants (balanced for gender) completed the study, which involved performing a simulated drive in one of three conditions along 24 mi of roadways. The three system-on groups represented the following information conditions: IVS plus navigation, navigation only, or IVS only. Each group also completed a baseline (system-off) condition. The driving performance results indicated that drivers complied with most speed zones whether IVS information was present or not; however, average speeds tended to be higher in the system-on conditions. Drivers in the IVS-only condition spent significantly less time looking at the in-vehicle display than drivers who were also presented with navigation information. Response time to a roadside visual detection task was significantly increased only in speed transition zones whether IVS information was present or not. This condition suggests that increased driver workload occurs during transitions to a new speed zone, particularly when drivers are required to search the environment for additional visual information (e.g., signs, pedestrians, other vehicles).