It's a song about the fantasy of driving your car into oncoming traffic. It's essentially a suicide song. It captures that feeling of driving alone at night, pondering your life, listening to the engine. She says 'the rhythm of the engine always makes me empty', as though there is something that draws us into that feeling that we are simply part of the great machinery of society, as we lose all sense of individuality and self. The urge to smash the machine, the sudden flash of impact and the feeling of flying through the air surrounded by shards of broken glass and the distant sound of a siren become so compelling, so hypnotic that it becomes a fantasy of how to break out of the prison of life that surrounds us.
For such a short song, it's actually pretty deep. I love it.