This report describes further analysis of data from the advanced collision avoidance system (ACAS) field operational test, a naturalistic driving study. To determine how distracted and nondistracted driving differ, a stratified sample of 2,914 video clips of the drivers’ faces and forward scene was coded to identify (1) where the driver was looking, (2) where their head was facing, (3) the secondary task performed, (4) what their hands were doing, and (5) the driving conditions. A sample of the clips from the first pass (balanced to equalize distracted and nondistracted clips) was examined frame by frame. Key findings include: 1. The most common secondary tasks were conversing, chewing gum, grooming, and using a cell phone, in that order. The most common subtasks were conversing on a cell phone, chewing gum, grooming with a hand, and biting one’s lips while chewing gum, in that order. 2. Depending on the analysis, 7 to 16% of all secondary tasks involved 2 or more secondary tasks occurring together, with 9 of the 10 most common combinations involving conversation or chewing gum. 3. Conversation tended to occur more frequently for older drivers and women, and on minor roads; and less often between midnight and 6:00 a.m., and when the outside temperature was below freezing. 4. Using the phone occurred more frequently for young drivers, for men, and in lighter traffic; and less often between midnight and 6:00 a.m. (Author/publisher)
Abstract