On normal vehicles, there is a confusing between the rear wings and spoiler. The difference between a rear wing and a rear spoiler is that spoilers are designed to reducing lift and improve fuel economy instead of create downwards force. With flow of air at the rear of the vehicle becoming turbulent and a created low-pressure zone that increases the drag and instability, some synergy can be applied to spoilers and vortex generators to improve the vehicle aerodynamic performance. With a longer, gentler slop or angle of attack from the roof that was improved by other aerodynamic device, the spoiler helps delay flow separation of the fast moving air and increases the flow dynamics just as the vortex. This decreases drag, increases fuel economy, and helps keep the rear window clean.
