This report by Professor Frank McKenna examined the role of sleep hygiene (those factors that promote or disrupt effective sleep) on human performance, and investigated the relationship between sleep hygiene and crash involvement. Measures of sleep hygiene and crash involvement were considered for a sample of over 6000 drivers. It was found that poorer sleep hygiene was associated with younger age and greater crash involvement. The association between sleep hygiene and crash involvement remained when age and risk taking had been taken into account. The report concludes that poor sleep hygiene is associated with poorer performance as measured by crash involvement.