A vehicle soft impact detection system uses a piezo film mounted to a
front vehicle bumper. The piezo film is selected and mounted to have a
greater sensitivity to low-frequency shock waves as compared to
high-frequency shock waves, the frequency and amplitude is then compared
to a selected range of frequencies and amplitudes that are indicative of
a crash with a soft tissue body. In a further embodiment the output of
the piezo film is compared with the output of a second sensor which is
more sensitive to high-frequency shock waves than to low-frequency shock
waves such as a Terfenol-D based sensor.