Traffic accident increase from carelessness driving is a serious problem in society with falling asleep at the wheel being responsible of about 23% of all traffic accidents. Distinct features in heart rate signals during the driver’s wake and sleep states could provide an initiative for the development of a safe driving systems such as drowsiness detecting sensor in a smart wheel. We measured ECG from 5 adult subjects during the wake and sleep states. After detecting R-peaks in ECG signal, heart rate signal was obtained. Heart rate variability was investigated for three different frequency regions; very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF). The average power in VLF and LF frequency band increased from 14% to 21.6% and 38.87% to 40.53% respectively, while for HF band it reduced from 47.2% to 37.83%. The LF/HF ratio for sleep state (1.126) was larger than for wake state (0.082). In conclusion, there are changes in heart rate from wake to sleep that are potentially to be detected. The results in our study could be useful for the development of drowsiness detection sensors for effective real-time monitoring.