Impact of Changing Demographics on the Transportation System Panel
Chaired by Joseph Coughlin

Description: The 88th Annual Meeting of the Transportation Review Board featured the research panel: “Impact of Changing Demographics on the Transportation System.” Lead by Joe Coughlin, the panel presented information vital to government, universities and the private sector on the topic of transportation demographics. Presentations identified a variety of critical forces that will shape systems of transportation over the next 20 years including: aging and demographic transition, immigration internally and abroad, changing racial and ethic mix, and gender differences. These demographic forces will continue to impact the transportation workforce, transportation system demand and safe mobility in the near and distant future. To learn more, click here to visit the Transportation Review Board’s Conference webpage.

Cognitive Task Complexity and the Impact on Drivers’ Visual Tunneling
Presented by Bryan Reimer

Abstract: Cognitive distractions have been shown to adversely impact drivers and are a leading cause of accidents. Research indicates that drivers alter how they allocate their visual attention while engaging in cognitive secondary tasks. To evaluate the potential impact of cognitive secondary tasks on the allocation of driver’s visual attention and vehicle control, we presented drivers with increasingly complex forms of an auditory cognitive task while driving in an instrumented vehicle. Measures of vehicle performance and eye gaze were assessed. Consistent with theories on visual tunneling, drivers’ gaze distributions were significantly smaller while performing certain levels of the secondary task, thereby reducing peripheral vision. During the most difficult level of the secondary task, gaze dispersion was smaller relative to any other level of the task. Results indicate that changes in visual attention may provide earlier indications of cognitive distraction than changes in vehicle control, the latter of which was only observed during the most difficult level of the secondary task. Observed changes in vertical eye position suggest that drivers compensated for moderate cognitive demands by increasing their sight distance before further incremental increases in workload exceeded drivers’ abilities. In conclusion, this study provides evidence that current research efforts are not adequately addressing the impact of incremental increases of cognitive distraction on driver performance. Finally, although current legislative efforts focused on hands-free cellular phone usage may be well intended, it is clear that any on-road communication increases cognitive workload thereby decreasing drivers’ peripheral vision and reducing safety.

The Impact of Incremental Increases in Cognitive Workload on Physiological Arousal and Performance in Young Adult Drivers
Presented Bruce Mehler

Abstract: This study examined the sensitivity of heart rate, skin conductance and respiration rate as measures of mental workload in a simulated driving environment. Workload was systematically manipulated using increasingly challenging levels of a cognitive secondary task. In a sample of 121 young adults, heart rate increased incrementally with increasing task demand. Significant elevations in skin conductance and respiration rate were also observed while secondary task performance was nearly perfect and prior to the appearance of decrements in indices of driving performance. All three physiological measures appeared to peak at the same point that a subtle drop in simulated driving performance became detectable. Taken together, the pattern of results indicates that physiological measures can be sensitive to changes in workload prior to decreases in driving performance measures. These findings further highlight the value of utilizing appropriate laboratory type physiological recording techniques to measure mental workload in product design and functionality research. They are also generally supportive of work exploring the potential for incorporating physiological measures of driver workload and attention state in future safety systems.