a collision detection sensor system including:

a conductive pattern disposed on a front surface of a shock absorber of a vehicle bumper, the conductive pattern being configured to form an electromagnetic field by an application of alternating current power, and

a conductive material disposed at a position facing the conductive pattern on an inner surface of a bumper skin of the vehicle bumper; and

a control unit comprising at least one circuit configured to determine an occurrence or non-occurrence of a pedestrian collision based on a change of a current flowing in the conductive pattern, wherein the at least one circuit of the control unit is configured to calculate a mass and a stiffness of a colliding object based on the magnitude of the peak value of the current flowing in the conductive pattern and the vibration frequency of the peak value and, based on the determination result, determine whether the colliding object is a pedestrian by comparing the calculated stiffness with a set range indicative of a pedestrian stiffness comprising a maximum stiffness value and a minimum stiffness value and the calculated mass with a pre-defined value.