Countermeasures to driver sleepiness: is the message g etting through ?

1. Countermeasures to driver sleepiness: is the message getting through? A J Filtness, L A Reyner Sleep Research Centre, Loughborough University, Loughborough, UK, LE11 3TU Corresponding author: a.j.filtness@lboro.ac.uk • Summary • The most effective countermeasures to driver sleepiness (caffeine and a nap, ideally in combination) are not the most popular choice for UK drivers. • Groups susceptible to driver sleepiness (OSA patients and truck drivers) do not favour effective countermeasures to driver sleepiness. • Prior experience of driver sleepiness does not promote an effective choice of countermeasure. • Introduction • We investigated if the current UK government advice was being followed by two groups of drivers susceptible to driver sleepiness; • Obstructive Sleep Apnoea (OSA) patients • Truck drivers • Does prior experience of driver sleepiness result in more effective choice of countermeasure? • Drivers know when they are sleepy (Reynerand Horne, 1998) so have opportunity to take action before a possible incident. The most effective countermeasures to driver sleepiness is the combination of caffeine and a nap (Reyner and Horne, 1997), advice now incorporated into the UK Highway Code (safe driving manual issued to all UK drivers), along with taking a break from driving every 2 hours (DVLA 2010). Experienced drivers are required to keep up to date with changes to the Highway Code of their own volition. • Method • Participants: 20 OSA, CPAP treated car drivers, 20 control car drivers and 148 truck drivers • Protocol: OSA and control car drivers were surveyed in the Sleep Research Centre, all drove less than 3h per week. Truck drivers were surveyed at a major ‘truck stop’. • Questions: • Have you ever felt sleepy when driving?Yes/no • Do you ever think you have fallen asleep when driving? Yes/no • How long do you drive for before you stop and take a break? • If you felt drowsy whilst driving which statements best describe what you are most likely to do? (You many answer more than one) • Keep going to reach your destination as soon as possible • Stop at a service station and have a nap • Turn the radio up • Stop at a service station and have a high caffeine content drink • Open a window • Stop at services and stretch your legs Results • Figure 1: • - OSA participants are most likely to have felt sleepy while driving and truck drivers least likely. • Significantly more OSA participants had fallen asleep while driving than controls (X²= 6.82(1), p=0.009). • Truck drivers were the least likely to have fallen asleep while driving. Figure 2: - Opening a window and having a walk (stretch legs) were the most popular countermeasures. - To keep going was least popular, showing each group would take some action. Figure 1: Experience of driver sleepiness, by group Figure 2: Choice of countermeasure, by group Figure 3: - OSA participants are more likely to take a break from driving every 2h than controls, (nsd). - Truck drivers all reported driving within EU driving law (not shown in figure). Figure 4: - Opening a window and having a walk (stretch legs) were the most popular with both groups. - Those with experience of driver sleepiness were no more likely to choose the effective countermeasures. Figure 3:Adherence to driving time advice, by group Figure 4: Choice of countermeasure, by driver sleepiness experience Conclusion The UK government is providing valid advice on counteracting driver sleepiness, despite being introduced in 1999 this advice is still not being followed. Drivers are still choosing to open a window and stretch their legs, (advice in the “Highway Code” before 1999 when all participants took their driving tests) which has been shown to be ineffective (Reyner and Horne, 1998). Two groups of drivers at increased susceptibility to driver sleepiness are no better at choosing effective sleepiness countermeasures than controls. Having experience of previously fallen asleep while driving does not result in being more likely to choose an effective countermeasure than those who have not. An awareness campaign is needed to provide experienced drivers with accurate information on how best to deal with sleepiness. References DVLA (2010), Rule 91 for drivers and motorcyclists. Retrieved 23/05/2010, from http://www.direct.gov.uk/en/TravelAndTransport/Highwaycode/DG_069855 Reyner and Horne (1998), Falling asleep whilst driving: are drivers aware of prior sleepiness? Int J Legal Med, 111: 120 – 123 Reyner and Horne (1998), Evaluation of In-Car Countermeasures to Sleepiness: Cold Air and Radio. Sleep, 21(1): 46- 50 Reyner and Horne (1997), Suppression of sleepiness in drivers: Combination of caffeine with a short nap. Psychophysiology, 34: 721 – 725