The journalism student who was chauffeuring David Halberstam when the Pulitzer Prize winner was killed said Tuesday he jumped at the chance to spend time with the writer and is grief-stricken at what happened.

“I want to apologize to his family because I feel so bad,” said Kevin Jones, 26, who is in his first year of a two-year program at the University of California, Berkeley Graduate School of Journalism. “I just wanted to help him.”

Although police have not established who was at fault in Monday’s crash, Jones said he felt responsible for the safety of his celebrated passenger.

An autopsy conducted Tuesday showed Halberstam, who was wearing a seat belt, died almost instantly when a broken rib punctured his heart, San Mateo County Coroner Robert Foucrault said. The cause of death was listed as multiple blunt force trauma.

Jones was driving through an intersection with a traffic light when another car broadsided his, smashing into the passenger side, authorities said. Police said they were interviewing witnesses.

Halberstam, the author of 21 nonfiction books, was at work on a new one about the legendary 1958 NFL championship game between the Baltimore Colts and the New York Giants. Jones was taking him to interview Hall of Fame quarterback Y.A. Tittle, who lives south of San Francisco.

Jones, who suffered a small puncture in one lung, said he received an e-mail from the journalism school last Friday saying Halberstam was looking for a driver who would get $20 an hour and a one-on-one journalism lesson.

Jones was the first one to reply.

“He is one of those people you can’t say his name without saying Pulitzer Prize-winning author,” Jones said. “I’m a journalist and that deserves the utmost respect.”

Halberstam’s interview had been set for Saturday but was rescheduled for Monday morning, according to Jones. During the hour they spent in the car, they spoke about having children and about how Jones’ wife and Halberstam’s daughter were teachers.

Jones, who has hired a lawyer, would not discuss the crash itself. But he repeatedly expressed a desire “to make some kind of tribute” to the man who reached the pinnacle of his profession and spent the last hour of his life giving advice to a man just beginning his career.