How did ponyboys parents die? From the book "The outsiders"

Ponyboy's parents died in a car accident a few years before the events in the novel take place. The book never actually tells when the accident occurred but it's safe to assume it was somewhat recent as Ponyboy still has a memory of his parents.

Ponyboy's parents were killed in a car crash, which is why Sodapop and Danny takes care of him (with Danny as his legal guardian).