The word "metallic" is used to describe the voice that emanates from the police cruiser because it does not actually seem to be coming from a human being; the voice appears to be coming from the car itself. When Leonard Mead is stopped by the car, he carries on a conversation with some metallic voice, and he cannot see a person, we are led to believe, because of the lights shining in his eyes. However, once he is instructed to get in, he must walk past the car's front windows, and the man sees that no one is in the front seat of the car; in fact, "there was [...] no one in the car at all." Everything inside the vehicle is described as "metallic" as well, and, soon, the voice is described again as "iron."

Further, when Leonard Mead asks the car where it is taking him, it seemed to hesitate and make a number of "whirring click[s]" as though it were sorting through potential locations until it finally lands on the appropriate one. This makes it seem as though the car is actually doing the talking and making all the decisions via some kind of futuristic computer system, and this is why the voice is described as metallic: because the car is made of metal, and it is the car's voice Leonard Mead hears.