For this project, researchers used an existing dataset from a previous research effort to investigate the moth effect theory, where it is believed that drivers drift toward bright lights. While the previous research study primarily focused on signs, on one segment of the closed-course participants drove past a law enforcement vehicle with its overhead flashing lights activated at two blood alcohol concentration (BAC) levels (0.00 and 0.12 g/dL). Researchers also utilized the existing dataset to investigate how alcohol affects pupil size and vehicle speed. Within 300 ft of the law enforcement vehicle, all of the participants initially steered the vehicle away from the vehicle. However, about 250 ft upstream of the vehicle all of the participants began to drift back toward the vehicle and continued to drift toward the vehicle for approximately 200 ft, moving laterally 8 to 24 inches. Nonetheless, all participants kept the study vehicle well within in the lane lines. On average, participants drifted farther toward the law enforcement vehicle at a BAC level of 0.12 g/dL. However, the effect of BAC level on lane placement varied by participant. Researchers confirmed that the pupil diameter for the majority of participants was larger at a BAC level of 0.12 g/dL than at a BAC level of 0.00 g/dL. Participants at a BAC level of 0.12 g/dL also tended to look directly at the law enforcement vehicle less. Small differences in the vehicle speed between BAC levels were seen; however, the differences were practically negligible. Typically, the participants at the 0.00 g/dL BAC level appeared to drive more conservatively. Overall, the vehicle lane placement findings upstream of the law enforcement vehicle support the moth effect theory. In addition, the pupil diameter findings confirmed expectations regarding bright light sources and alcohol-impaired driving. (Author/publisher)
Abstract