Conversation so far:
How did Ernie Kovacs die?
Ernie Kovacs was killed in a car accident in Los Angeles during the early morning hours
When did Ernie Kovacs die?
Kovacs was killed in a car accident in Los Angeles during the early morning hours of January 13, 1962.
Were drugs or alcohol involved in Ernie Kovacs' death?
images of Ernie Kovacs dead appeared in newspapers across the United States. An unlit cigar lay on the pavement, inches from his outstretched arm.
Was Ernie Kovacs the only person to die in the car accident?

Question: What caused his car accident?
Self-contained rewrite: What caused Ernie Kovacs' car accident?