The Horses of the Horsemen are not actual horses, but automobiles that serve as transport for the Four Horsemen of the Apocalypse, each bearing a color corresponding to that of their rider. They aren't exclusively used because the Horsemen actually need them, but more to keep in context of tradition and lore.
Representing War's red steed, this Mustang is driven during the Apocalypse. War presumably uses it to enter a small town, leaving it parked when not in use. When Sam and Dean incapacitated War by cutting off his ring finger, War's Mustang vanished with him.
Famine's Black Cadillac EscaladeEdit
Representing Famine's black steed, this Cadillac is driven by low-level demons due to Famine's weakened state. After a small town is touched by Famine's effect, Famine and his demons drive in the Horseman's Cadillac to a local diner.
Pestilence's AMC Hornet WagonEdit
Representing Pestilence's green steed, this Wagon is driven during the Apocalypse. Pestilence drove it to a drug store when stopping there to buy flu medicine. The Wagon's license-plate reads SIKN TRD, translating to "sick and tired".
Death's 1959 Cadillac Series 6200 Coupe Edit
Representing his pale steed, this Cadillac is driven during the Apocalypse sometime after the rising of Death. Death drives it in Chicago, Illinois. The Cadillac's license-plate reads BUH*BYE, translating to "bye bye".
- Death's car model was dubbed a 'death car' in real life due to urban legends tying the car to deaths of people.