1. A system for determining whether a driver of a vehicle is drowsy, the system comprising: a steering wheel sensor for generating a steering wheel signal; a processor for extracting at least one feature of the steering wheel signal based on an empirical mode decomposition, determining whether the driver is drowsy based on the at least one extracted feature, and generating an alarm signal in response to determining that the driver is drowsy; and, an alarm device for indicating that the driver is drowsy, or a safety mechanism for controlling the vehicle, wherein the alarm device or safety mechanism receives the alarm signal from said processor and is activated in response to the alarm signal.