System for detecting abnormal driving behavior

A program product usable for an abnormal driving behavior detection system for a vehicle, the program product comprising:

• a non-transitory computer-readable medium;
• and
• a set of computer program instructions embedded in the computer-readable medium, the instructions causing a computer of a security system to:
• repeatedly obtain an observed value indicative of at least one of a running condition of the vehicle and a driver's driving operation of the vehicle;
• calculate, each time an observed value is obtained at a given obtaining timing as a target obtained value, a mode probability for each of a plurality of driving modes as a function of one or more previous observed values previously obtained before the target obtained value, each of the plurality of driving modes being defined by modelling a group of normal driving behaviors, the mode probability for each of the plurality of driving modes representing a probability that a target driving mode at the given obtaining timing corresponds to a corresponding one of the plurality of driving modes;
• obtain, for comparison with the target obtained value, a predicted observed value for each of the plurality of driving modes using a driver's normal behavior model defined for a corresponding one of the plurality of driving modes;
• calculate a deviation of the target observed value from the predicted observed value for each of the plurality of driving modes;
• and
• determine whether there is at least one driver's abnormal behavior based on the mode probability for each of the plurality of driving modes and the deviation calculated for each of the plurality of driving modes.