An alarm system module for an automobile includes: a logic circuit; an actual
vehicle speed value input configured to receive an actual vehicle speed value from
the automobile; a state selection input configured to receive a state selection
instruction from a user; and a synthetic vehicle speed value output configured
to output a synthetic vehicle speed value to the automobile. The logic circuit
is configured so that, when the alarm system module is in the disarmed state, the
synthetic vehicle speed value is approximately equal to the actual vehicle speed
value, and when the alarm system module is in the armed state, the synthetic vehicle
speed value is greater than a threshold value of approximately 2.5 km/hr.