Effect of Distraction Task on Driving Performance of Experienced Taxi Drivers

Background: Driving performance is influenced by human, vehicular, and environmental factors. Objectives: To investigate the effects of distraction tasks, such as sending a text message (STM) and searching a navigation device (SN), on the driving performance of experienced taxi drivers. Methods: Twelve male taxi drivers (age: 56.3 +/- 4.4 y; experience: 28.4 +/- 6.4 y) and 14 female taxi drivers (age: 55.5 +/- 3.5 y; experience: 19.4 +/- 5.0 y) drove in a simulator at a constant speed (90 km/h) for 2 min while maintaining a gap of 30 m from the car in front, also traveling at 90 km/h. Participants were instructed to drive only for the first 1 min (control phase). For an additional 1 min (task phase), they were instructed to drive only, drive + STM, or drive + SN. Results: Compared with driving only, during driving + STM or driving + SN, the drivers' skin conductance level was relatively increased, suggesting that the distraction task increased the drivers' workload and sympathetic nervous system activity. Compared with driving only, during driving + STM or driving + SN, the average distance from the car in front, speed deviation, and anterior-posterior and medial-lateral coefficients of variation increased, suggesting that maintaining the instructed gap and speed, and the longitudinal and transverse control of the car, was more difficult because of the distraction task. Conclusions: Even for highly experienced taxi drivers, distraction tasks increased workload, increased the difficulty of vehicle control, and detracted from safe driving.