What's behind me and why should I care? I'm driving down the highway and I'm certainly not going to back into something! There are at least two common hazards that occur regularly behind every driver and looking out for them is just good sense.
The first hazard is the impatient driver that follows you too closely. Identify this hazard and you can avoid it by either slowing down or even pulling over and stopping. If you choose to slow down, you increase your own following distance and allow even more time to react if something happens. In a sense, you are thinking ahead for the dummy behind.
The second hazard is the vehicle that is rapidly overtaking you. Anticipating a foolish passing move, postponing a left turn even though your signal light is flashing or deciding that this is not the time to stop suddenly could be very important to you!
For these reasons and more, it is wise to know what is around you when you drive. Scanning your mirrors briefly every 5 to 10 seconds will help you keep that big picture fresh and give you the time you need to decide how to avoid trouble. You must know what is behind you and you should care! Reference Links