When pivoted-up by an electric motor, it acts as a roof spoiler, which also vents air from the interior and increases rear passenger headroom.
en.wikipedia.org In a descent without spoilers, air speed is increased and the engine will be at low power, producing less heat than normal.
en.wikipedia.org By so doing, the spoiler creates a controlled stall over the portion of the wing behind it, greatly reducing the lift of that wing section.
en.wikipedia.org Later additions, including fender flares, spoilers, carburetor covers, and bumpers, progressively changed the aesthetic values of the car.
en.wikipedia.org Major differences were the addition of side skirts, a small spoiler and distinctive orange and silver pin striping.
en.wikipedia.org