An Evaluation of the Effects of a Functional Energy Drink on Post-lunch and Early Evening Driving Performance

This paper reports the results of a pilot study designed to evaluate the effect of an energy drink on mental performance and driving. 24 healthy subjects were tested after consumption of a placebo or an energy drink in a double-blind crossover study. Measures included a laboratory test of Adaptive Tracking (AT), and a simulated drive involved a 40 Km motorway route in an advanced motion-based simulator. Self-report scales of sleepiness revealed a significant difference between placebo and energy drink. Though both drinks provided an alerting effect, both the level and duration of the effect observed after consumption of the energy drink was greater. Performance on the AT task was significantly improved. This improvement in hand-eye coordination was reflected in better lane-keeping performance in the simulated driving task. There was also a consistent tendency when the drivers drank placebo to drive slightly faster in traffic than when drinking the energy drink. These preliminary findings, which demonstrate that consumption of even a relatively small volume (250ml) of an energy drink can have an effect on sleepiness, lane keeping and speed choice in simulated traffic, could have implications for future highway safety.