mbkicks,

I see that you're new here, but some advice: probably you should check the site before suggesting an idea. This idea--though faulty from an engineering point-of-view-- is generally suggested about once a month.

Thanks for trying.

problem = you are spending energy to create the forward momentum of the vehicle. you would then reduce the forward momentum of the vehicle by introducing drag by adding the wind turbine thus requiring greater energy usage by the vehicle. if this were not the case then you would basically have a perpetual motion machine...

Although not an engineer, I agree with the comment that this spinner thing is counterproductive for the car itself...

When I fist saw the post, though I was thinking of something different -- vertical axis "windmill" devices that could be placed either alongside roads, but particularly at underpasses to road and especially freeway bridges (higher speeds) and capture the wind from the passing cars, trucks, buses, etc. Could also work for trains passing through towns, through tunnels, etc.

Capturing some of the wind that passes through in these "funneled" areas could be used to charge batteries to run remote off grid streetlights, light road signage, etc. or maybe just to trickle charge the grid or provide boosts to long distance transmission lines. Of course the economics have to be worked out on embodied energy and EROI-- but in general it's a sort of co-generation scheme == using the momentum of vehicles already in motion with little energy cost plus it would be constant on busiest highways, etc.