So they would need to enter into a secret agreement with a foreign government, create secret facilities, ship the car around the world, still make their cars in

So they would need to enter into a secret agreement with a foreign government, create secret facilities, ship the car around the world, still make their cars invisible and ethereal, just so they could test their SDCs in real traffic? The plot thickens. Add a couple rocket launchers and you have a Hollywood blockbuster.