Extended Visual Glances Away from the Roadway are Associated with ADHD- and Texting-Related Driving Performance Deficits in Adolescents

Abstract

The purpose of the research study was to determine whether ADHD- and texting-related driving impairments are mediated by extended visual glances away from the roadway. Sixty-one adolescents (ADHD =28, non-ADHD =33; 62% male; 11% minority) aged 16-17 with a valid driver's license were videotaped while engaging in a driving simulation that included a No Distraction, Hands-Free Phone Conversation, and Texting condition. Two indicators of visual inattention were coded: 1) percentage of time with eyes diverted from the roadway; and 2) number of extended (greater than 2 s) visual glances away from the roadway. Adolescents with ADHD displayed significantly more visual inattention to the roadway on both visual inattention measures. Increased lane position variability among adolescents with ADHD compared to those without ADHD during the Hands-Free Phone Conversation and Texting conditions was mediated by an increased number of extended glances away from the roadway. Similarly, texting resulted in decreased visual attention to the roadway. Finally, increased lane position variability during texting was also mediated by the number of extended glances away from the roadway. Both ADHD and texting impair visual attention to the roadway and the consequence of this visual inattention is increased lane position variability. Visual inattention is implicated as a possible mechanism for ADHD- and texting-related deficits and suggests that driving interventions designed to address ADHD- or texting-related deficits in adolescents need to focus on decreasing extended glances away from the roadway.

Figure 1. Hypothesized Mediation Model for the Effect of Diagnosis on Lateral Position via Visual Inattention

Note. SDLP = standard deviation of lateral position; # >2 secs = number of lookaways greater than 2 seconds; c’ = the indirect effect of ADHD on SDLP when visual attention is included as a mediator during the texting condition. a, b, c, and c’ are all unstandardized regression coefficients.

Figure 2. Path Coefficients for Simple Mediation Analysis on Standard Deviation of Lateral Position During the Texting Condition

Note. SDLP = standard deviation of lateral position; SE = standard error; # >2 secs = number of lookaways greater than 2 seconds; c’ = the indirect effect of ADHD on SDLP when visual attention is included as a mediator during the texting condition. a, b, c, and c’ are all unstandardized regression coefficients.