Chris, the cops didn't do anything because there's nothing to corroborate the incidence. However, it's called assault and in most places its a crime and you can press charges, even without a witness. A confrontation becomes assault at the moment you feel threatened. When he said he would run you down, meaning he would use his car, it became assault with a deadly weapon, a felony in every state. If you're up to it, ask the cops what if he had showed a weapon, like a hand gun or baseball bat? a car is no different.