Previous research suggests that cognitive performance can be improved following consumption of snacks (Benton, Slater and Donohoe, 2001; Mahoney, Taylor and Kanarek, 2005) and caffeinated drinks (Lieberman, 1992). Consumption of snacks leads to increased ratings of alertness and other aspects of mood and improved performance on recall memory (Benton, Slater and Donohoe, 2001). Consumption of caffeinated drinks led to improvements in reaction time, attention and alertness (Brice and Smith, 2001). What is now of interest is whether these improvements can be translated to real life activities such as driving. Much research has been conducted looking at the effects of alcohol and caffeine on road traffic accidents and performance on a driving simulator.Alcohol has been found to increase the risk of a crash (McClean, Holubowycz and Sandow, 1980), significantly increase the time taken to respond to hazards (West et al., 1993), slow reaction times and increase body sway (Liguori et al., 1999). In contrast caffeine can reduce driver fatigue, a leading cause of road crashes (Reyner and Horne, 2002), decrease steering wheel movements (Brice and Smith, 2001), decrease lane drifting and improve reaction times (Horne and Reyner, 2001).