This scientific poster presents a study that explores the perception of drowsiness in crashes where the driver has fallen asleep. Subjects in the study were 312 drivers involved in recent North Carolina crashes who were reported by the investigating officer to have fallen asleep prior to crashing; 71% were male, with a mean age of 35.5 years. Subjects were contacted for a telephone interview. Interview data were combined with the police crash report data. Some results are as follows: (1) Only half the drivers reported feeling very drowsy (37%) or moderately drowsy (16%) prior to crashing; (2) The rest reported feeling either slightly (21%) or not at all (23%) drowsy; and (3) yet most agreed with the investigating officer that their crash was sleep-related. Using statistical techniques, variables associated with perceived drowsiness prior to crashing were identified and five of these variables were included in the final best model for predicting perceived drowsiness prior to crashing: driver age, times driven drowsy in the past year, Epworth Sleepiness Score, use of a soporific medication, and police-reported alcohol use.
Abstract