Why is Willy home? Why is Linda alarmed that he's home?

He says that he is too tired to finish his trip. He says he was falling asleep and swerving off the road. Linda is worried about Willie in general. She thinks he works too hard and should not be traveling any more. She attributes Willie's swerving to bad steering in the car. She is also worried that he has smashed up the car again when he first returns.