Keep your eyes on the road: young driver crash risk increases according to duration of distraction

Abstract

Purpose: Secondary task engagement that distracts the driver is a contributing factor to motor vehicle crashes among adults. However, the association between eye glance duration and crash risk with novice teenage drivers has not been determined.

Methods: Vehicles of 42 newly licensed teenage drivers were instrumented with cameras, accelerometers, Global Positioning System(s) (GPS), and other devices. Data were collected continuously for 18 months. Crashes and near crashes (CNCs) were identified by examining highly elevated gravitational force events. Video footage of the 6 seconds prior to each CNC and randomly sampled non-CNC road segments were coded for the duration of eye glances off the forward roadway and the presence of secondary task engagement. The likelihood (odds ratios) of CNC due to eye glance behavior was calculated by comparing the prevalence of secondary task engagement and duration of eyes off road prior to CNC with the prevalence and duration of eyes off road during non-CNC road segments.

Results: Crash risk increased with the duration of single longest glance during all secondary tasks (OR=3.8 for >2 s) and wireless secondary task engagement (OR=5.5 for >2 s). Single longest glance provided a more consistent estimate of crash risk than total time eyes off the forward roadway.

Conclusions: Those eye glances away from the forward roadway involving secondary tasks increased the likelihood of CNC. The longer the duration of eye glance away from the road the greater the risk, regardless of type of secondary task. Education and policy discouraging secondary task engagement, particularly for prolonged periods, is warranted.

Keywords: Adolescents; Cell phone use; Naturalistic driving methods; Risk taking; Secondary task; Teenage driver.

Copyright © 2014 Society for Adolescent Health and Medicine. All rights reserved.

Figures

Figure 1

CNC likelihood for five durations of single longest single glance off forward roadway (LGOR) involving (A) All Secondary Tasks; (B) Wireless Secondary Tasks.* s = seconds * >1 included the glances in the other categories’ >2 included glances in the categories >2, >3; etc.; separate models were fitted for each threshold value for LGOR and TEOR to avoid issues of non-independence.

Figure 1

CNC likelihood for five durations of single longest single glance off forward roadway (LGOR) involving (A) All Secondary Tasks; (B) Wireless Secondary Tasks.* s = seconds * >1 included the glances in the other categories’ >2 included glances in the categories >2, >3; etc.; separate models were fitted for each threshold value for LGOR and TEOR to avoid issues of non-independence.

Figure 2

CNC likelihood for five durations of Total Time Eyes Off Forward Roadway (TEOR) involving (A) all secondary tasks and (B) wireless secondary tasks.* s = seconds * >1 included the glances in the other categories’ >2 included glances in the categories >2, >3; etc.; separate models were fitted for each threshold value for LGOR and TEOR to avoid issues of non-independence.

Figure 2

CNC likelihood for five durations of Total Time Eyes Off Forward Roadway (TEOR) involving (A) all secondary tasks and (B) wireless secondary tasks.* s = seconds * >1 included the glances in the other categories’ >2 included glances in the categories >2, >3; etc.; separate models were fitted for each threshold value for LGOR and TEOR to avoid issues of non-independence.