Patent ID: 8648728

Claim:
Apparatus for use with a motor vehicle, the apparatus comprising: an interlock device, the interlock device being adapted to, in use: at least while said vehicle is in motion, periodically generate a prompt; assess motion of said vehicle; only when said vehicle is assessed by said device to be at rest, carry out an analysis operation wherein a breath sample is received and analyzed; and in the event that, within a predetermined period following a prompt, the device does not, while said vehicle is assessed to be at rest, carry out said analysis operation, enter an alarm state in which one or more of the following are actuated at least when the vehicle is in motion: lighting forming part of the vehicle; auxiliary lighting carried by the vehicle; the horn of the vehicle; auxiliary horn carried by the vehicle; an event recording circuit; and an immobilizer circuit wherein one or more of the following conditions applies: the maximum attainable motor-driven velocity of the vehicle decreases as a function of vehicle location and/or speed, when the immobilizer circuit has been activated; the predetermined period is a function of vehicle location and/or speed; the intensity of an audio signal associated with the prompt varies as a function of vehicle location and/or speed; and the intensity of a visual signal associated with the prompt varies as a function of vehicle location and/or speed.