Driver errors and carelessness contribute most of the road accidents occurring nowadays. The major driver errors are caused by drowsiness, drunken and reckless behaviour of the driver. This paper focuses on a driver drowsiness detection system in Intelligent Transportation System, which focuses on abnormal behaviour exhibited by the driver using Raspberry pi single board computer. In the proposed system, a nonintrusive driver drowsiness monitoring system has been developed using computer vision techniques. Based on the simulation results, it was found that the system has been able to detect drowsiness in spite of driver wearing spectacles as well as the darkness level inside the vehicle. Moreover, the system is capable of detecting drowsiness within time duration of about two seconds. The detected abnormal behaviour is corrected through alarms in real time.