It’s not easy driving a truck for a living. You have large blind spots. Left turns are treacherous. Sitting down all day is bad for your back. Most importantly, you have to use the parking break when parking on a hill. Maybe everyone has to do that, but it’s easy to forget when you’re worrying about all those other things.
This FedEx driver made that mistake even though the neighborhood dogs were trying to warn him. They were barking at him even before the accident happened. Maybe they could sense it coming in the same way that some animals can sense impending earthquakes and natural disasters.