[Bulky]

The ones I have seen for a car, could be mounted under the floor board. With your food off of the brake, the plunger would be all the way in and the lights are off, as you step on the pedal, it moves the pedal away from the plunger, the plunger comes out and the tail lights go on. Then you would let go of the pedal and it would depress the plunger again an the lights would go out.