Wind powered motor vehicle - concept

Recently a bug hit my head - seeing the gas prices sore so high and also hearing all hues and cries all day at CNN, i thought over alternative energy resource. Yesterday evening i sat down with a clean paper sheet and made some designs of how a windmill can be installed over a mobile vehicle. Initially all the thrust would be derived from a battery which would then get charged as the vehicle derives its power from the wind energy. On a highway and also on roads, we see this huge surge of wind coming through the windows (if they are down). I wonder if we can make some ducts inside the car, which allow the wind to move inside an aerodynamic channel (pipe) which is twisted several turns below the car floor and finally hitting a wind turbine through a narrow duct with a high pressure. The ducts can be created at the front + sides (for max. wind gush) and the wind power can be stored in some batteries which would come in handy when the wind speed is slow or when the car is moving slow. Of course this idea requires automobile engineering (not my cup of tea.. :-)) but someone must have thought on similar lines to power vehicles using wind. Fuel cell is one other concept using renewable source of energy. Will upload some of the designs soon for the automobile guys to select/reject for their research...!!!

Friction is one issue....so then just create the ducts at the backend of the car and use tail wind to power your vehicle whenever you are moving in the direction of the wind and not against it....i.e. use wind, batteries and gas in transition to save fuel....howzzat!!