Naturalistic Driving Observations of Manual and Visual–Manual Interactions with Navigation Systems and Mobile Phones While Driving

Abstract

This paper discusses a naturalistic driving study on the use of mobile phones and navigation systems while driving. Manual interactions with these devices while driving can cause distraction from the driving task and reduce traffic safety. In this study 21 subjects were observed for 5 weeks. Their behavior was logged by four cameras, a Global Positioning System sensor, and a number of additional sensors. Results are presented on the durations and frequencies of manual interactions with the mobile phone and navigation system. Different manual subtasks with different levels of visual interaction are discussed, as well as how these interactions relate to driving speed. Results show that participants spent on average 1% of their driving time interacting with the navigation system and 4% of their driving time interacting with the mobile phone, excluding mobile phone conversations. For the mobile phone, 48% of the interactions took longer than 15 s; for the navigation system it was 40%. The average duration of a visual–manual subtask for the navigation system and the mobile phone was not significantly different when the task was performed while driving or while the vehicle was standing still. Exploratory analysis of vehicle speed suggests that drivers do not seem to adjust their speed while performing a visual–manual task. The results are discussed in relation to traffic safety and recommendations for future research.