Driving Anxiety in Individuals with Autism Spectrum Disorder

Background: Compared to 87% of the general population, only 25% of adults with Autism Spectrum Disorder (ASD) consider themselves independent drivers. Despite this low frequency of driving and its importance to overall quality of life, current transportation safety research among drivers with ASD is sparse and limited to survey data. These survey data have identified driving anxiety as a commonly reported driving barrier for individuals with ASD. Anxiety response comprises three components: physiological (i.e., increased heart rate), cognitive (i.e., anxious thoughts), and behavioral (i.e., avoidance of feared situations).

Objectives: The current study examined each of these components in individuals with ASD and the ability of anxiety to predict simulated driving performance.

Methods:  Sixteen drivers with clinical diagnosis of ASD and sixteen drivers with typical development (TD) matched on age (M_age = 22.94, SD = 4.25), gender (94% male), and driving experience (months since permit received; M = 93.41, SD = 50.39) were recruited. Participants wore a Polar activity sensor band to record average heart rate (AHR) – a physiological measure of anxiety – as they completed a 10-mile simulated drive. The simulator automatically collected driving performance outcomes. Participants also completed questionnaires assessing demographic characteristics, driving frequency (behavioral), and the Scale of Apprehensive Driving (SAD) assessing driving anxiety (cognitive). Independent samples t-tests were conducted to examine group (ASD vs TD) differences in driving frequency, as well as cognitive and physiological driving anxiety. Full factorial linear regressions were also conducted to examine diagnostic group, physiological and cognitive driving anxiety, and the interaction of anxiety and group (GroupxAHRxSAD) as predictors of driving performance. The continuous predictors (AHR, SAD) were centered to reduce multicollinearity when including the interactions in the model.

Results: Drivers with ASD (M = 4.31, SD = 2.75) drove fewer days per week (M = 6.19, SD = 1.52), t(30) = -2.39, p < .01, and showed higher self-reported driving anxiety (M = 23.88, SD = 3.70) compared to TD drivers (M = 23.88, SD = 3.70), t(30) = 2.14, p = .03. No group differences were found for AHR, t(30) = -.844, p = .95. Higher self-reported driving anxiety (F(4,29) = 3.24, p = .03) predicted slower driving speed. The linear regression indicated that neither group, AHR, nor GroupxAHRxSAD predicted other simulated driving performance outcomes (i.e., motor vehicle collisions, reaction time, lane deviation).

Conclusions: Drivers with ASD reported higher levels of driving anxiety, but showed no differences in AHR compared to TD drivers. Diagnostic group was not a predictor for driving performance; however as psychological anxiety symptoms increased, drivers tended to drive more slowly, possibly as a compensatory mechanism. These finding may suggest that drivers with ASD can regulate their physiological anxiety symptoms while driving, but may drive less often than TD drivers due to their anxiety’s psychological component. Study findings indicate diagnosis of ASD does not predict decrements in simulated driving performance. The current study suggests that targeting the psychological component of driving anxiety through evidence-based interventions (i.e., cognitive behavioral therapy) in the ASD population may increase rates of independent driving.