Abstract: A driver inattention detection system includes a rotary encoder (e.g., an optical rotary encoder) operably associated with a steering column of a vehicle and configured to produce steering signals representing the magnitude and direction of rotation of the steering column. A drive wheel concentrically coupled to the rotatable shaft of the encoder has a knurled peripheral edge that frictionally engages the steering column or a frictional band surrounding a portion of the steering column. A control module determines a steering count and if a driver inattention condition exists. The driver inattention condition exists if the vehicle is traveling above a minimum speed, and there has been no recent braking activity, and the active steering count is below a determined minimum threshold steering count. Separate first and second alarm modules operably coupled to the control module may be independently activated in a progressive manner. All sensed conditions and responses may be logged.