[spydyr]

The automatve industry is too focused on getting the XYZMobile aerodynamic on top. Even if they reach the point where they can add underpaneling to redirect airflow, it still has to compensate for the braking system and the exhaust.

Now instead of being cynical, I'm going to be constructive.

From what I have seen on the highway during wet weather, the air tends to flow out from under the car about 6-8 inches before the rear wheel well, and quite a bit is pumped out from thefront and back wheel wells themselves. Since it pumps out near the back wheel well it would be somewhat reasonable to assume that putting some spats and skirting around both the outside and inside of the rear wheels.

The interior skirts could help to prevent air from entering wheel well, and to direct the flow out to the rear of the car. The exterior preventing the same thing, but directing the flow around the body of the car.