A study published in Psychopharmacology on February 8 has confirmed that just one cup of coffee has a positive effect on prolonged highway driving in well-rested individuals.
“Drowsy driving is an important cause of traffic accidents and therefore, the development of effective countermeasures is essential,” the researchers from Utrecht University in the Netherlands said. “Consuming a cup of coffee is one of the most commonly used ways to combat driver sleepiness.”
“Up to now, the effects on driving performance of lower dosages of caffeine, e.g., a regular cup of coffee, have not been examined.”
In the study, 24 non-sleep deprived healthy volunteers drove for two hours in a driving simulator. Then took a fifteen minute break to consume either caffeinated or decaffeinated coffee. They then drove in the simulator for anther two hours.
Volunteers who consumed one cup of coffee, which contained 80mg of caffeine, were less likely to weave their car after driving for two hours in the simulator.
Those volunteers also did a better job of maintaining their speed, rated their driving quality as significantly more considerate, responsible, and safer, and felt less sleepy.
“Although additional mechanisms of action are involved, it is now believed that caffeine’s stimulant effects are exerted by antagonizing adenosine, primarily by blocking the adenosine A1 and A2A receptors,” the authors of the study explained. “Adenosine is considered to be a mediator of sleep.”