Driving and subsidiary behavior of taxi drivers working alternate-day shifts

A field study on taxi drivers working alternate-day shifts of prescribed duration of 16 hr of work revealed that most of them actually worked longer for 16 hr 50 min on the average, starting from 7:00 and ending later than 2:00. The mean hourly income greatly increased in hours later than 22:00 due to the increased fare per hire and higher speed, so that these hours were regarded by the drivers as the most important period of the day. This resulted in retarded mean bedtime of 5:31 after the shift end and in reduced sleep. The total rate of subsidiary activities of the drivers decreased during the middle of the day, but increased towards the shift end. Those activities having a relatively low rate at the beginning, such as subsidiary lower limb movements, shoulder-neck movements, and yawning, remarkably increased in the late evening and midnight hours. These activities increased even during frequent driving operations and tended to relate with each other, often recurring in bursts especially while feeling drowsy. The incentive wage system of the drivers thus accounts not only for the extraordinarily long working hours but also for intensified night work.