What are the two speakers talking about?

W: Now, Mr. Smith, did you see the accident clearly?
M: Oh, yes. I was standing outside the department store.
W: Do you know what time it happened?
M: Yes, it was 5:20 by my watch.
W: Was the truck going fast?
M: Yes. Well, perhaps the driver thought they were going to change to green. But they were red.
W: Are you sure, Mr. Smith?
M: Yes, absolutely sure.
W: Thanks a lot, Mr. Smith. Goodbye.
M: Goodbye.