Driving context influences drivers' decision to engage in visual–manual

· 2015 · . national safety council and elsevier ltd

DOI: 10.1016/j.jsr.2015.03.010

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Abstract

Journal of Safety Research 53 (2015) 87–96 Contents lists available at ScienceDirect Journal of Safety Research journal homepage: www.elsevier.com/locate/jsr Driving context influences drivers' decision to engage in visual–manual phone tasks: Evidence from a naturalistic driving study Emma Tivesten, a,b,⁎ Marco Dozza a a b Division of Vehicle Safety, Chalmers University of Technology, Gothenburg, Sweden Volvo Cars Safety Centre, Volvo Car Corporation, Gothenburg, Sweden a r t i c l e i n f

Summary

Naturalistic driving study (Tivesten and Dozza, J Safety Research) using 1,432 instrumented car trips to examine when drivers initiate visual-manual phone tasks (texting, dialing, reading; N=374 task instances). Driving context was coded from video, vehicle CAN signals, and map data (curvature, lead vehicle, passenger presence). Drivers initiated VM phone tasks more often while standing still and less often at high speed or with a passenger; they timed task onset to follow sharp turns, lane changes, and increasing lead-vehicle headway. Unlike prior simulator findings, drivers did not reduce speed during phone tasks.

Key finding

Experienced drivers self-regulate phone-task engagement using current and upcoming driving context (speed, curvature, headway trends, passengers), but they do not increase safety margins enough to absorb unpredictable lead-vehicle braking events.

Methodology

Exp 1: 10 participants, repeated measures across 6 sessions from 26 total. Exp 2: 20 participants, Old/New sequence comparison. On-road driving paradigm with DRT and NASA-TLX measures.

Sample size: Exp 1: N=10; Exp 2: N=20

Quality score: 5 / 5