Driver sleepiness due to sleep deprivation is a causative factor of many road accidents. Reducing the extent of the sleepy driving problem by developing a countermeasure device that will monitor the sleepiness level of the driver is crucial to improve the safety of the roads. Among numerous physiological measurements, the electroencephalographic (EEG) signal seems to be the most sensitive to detect sleepiness. Previous studies in the field have found consistent alterations of EEG signal during sleepy driving, though they face methodological limitations. We present here preliminary results from a real-driving experiment in which a more complete experimental setup was followed. The subjects were exposed to driving conditions twice: once after they had a normal sleep during the previous night, and once after they remained awake for at least 24 hours prior to the experiment. Significant alterations were observed in the alpha and beta EEG frequencies bands between the two sessions. Electroopthalmographic (EOG) measurements revealed an increased number of eye blinking during the sleep-deprived session in comparison to the control condition. Both measurements can be used for the successful design of a sleepiness detection countermeasure device.