This report describes the development of a new coding scheme to classify potentially distracting secondary tasks performed while driving, such as eating and using a cell phone. Compared with prior schemes (Stutts et al., first-generation UMTRI scheme), the new scheme has more distinctive endpoints for tasks and subtasks, is less subjective (e.g., no “high involvement” eating), includes codes for activities absent from prior schemes (e.g., chewing gum), and more closely links subtasks to visual, auditory, cognitive, and psychomotor task demands. The scheme has codes for 12 tasks (use a cell phone, eat/drink, smoke, chew gum, chew tobacco, groom, read, write, type, use an in-car system, internal distraction, and converse) plus codes for drowsiness. The scheme takes several factors into account, such as where the driver is looking, where the driver’s head is pointed, what the driver’s hands are doing, the weather, and the road surface condition. Each main task was divided into 3 to 17 subtasks (e.g., groom using tool, reach and get phone). This scheme was used to code video clips of drivers’ faces from the ACAS field operational test. In the first pass, 2,914 video clips were coded (for task, drowsiness, weather, and road) using custom UMTRI software. In the second pass, a sample of 403 distracted and 416 nondistracted clips were coded frame by frame (15,965 frames) for the subtasks performed, gaze direction, and where the head was pointed. (Author/publisher)
Samenvatting