Sleepiness is a significant workplace safety hazard and prevalent in shift workers including bus drivers. Several aspects of professional driving can result in shortened sleep and increased sleepiness, which has the potential to result in workplace injuries, incidents and crashes. Caffeine is an effective sleepiness countermeasure; however, private and professional drivers also report using potentially ineffective countermeasures such as sugar. By identifying factors which predict use of specific countermeasures (e.g., sugar, caffeine), educational initiatives could be targeted towards encouraging effective use. A subset of data was analysed from a driver sleepiness survey with London bus drivers (n=1,335). Univariate and multivariate logistic regressions were conducted to determine which factors separately predicted use of sugar (n=238) or caffeine (n=238) as a sleepiness countermeasure. Being female, having higher self-reported sleep quality and waking indexes and actively doing something to stay awake were predictive of sugar use. Age, sleeping pill use and actively doing something to stay awake were the strongest predictors of caffeine. However, many predictors from the univariate analyses were the same for both sugar and caffeine. Although tailored initiatives could be developed, broader education relating to managing sleepiness should be implemented for all bus drivers to encourage effective countermeasure use.
Keywords: Professional drivers; Road safety; Shiftwork; Sleep-related fatigue; Sleepiness; Workplace safety.