Here is car the concept of Super Terrain Vehicles (STVs) from Colorado-based Shadow Hawk Vehicles. Maybe this is the most ambitious and unrealistic concept cars ââ?¬Ë?under developmentââ?¬â?¢. Shadow Hawk Vehicles have apparently got six different models of their STVs: Steel Hawk, the Street Hawk, the Terra Hawk, the Desert Hawk, the Armor Hawk, and the ominous sounding Battle Hawk.