It's called a PARKING Brake

Anyone ever notice that little hand lever in the center of your car? You've probably ignored it all your life. I did an informal survey where I tracked how many people actually use this device, known as the Parking Brake. Guess what? Hardly anyone uses it.

It seems many people believe it's an "emergency brake" or that it only needs to be used on vehicles with a manual transmission. This is simply not so, it's called a Parking Brake. 

Go ahead, go grab your car owners manual and see what it calls the device and when you should use it. Got it now? That's right, engage the park brake every time you park. Not just when on a hill, or on a ferry or when you decide to get underneath it to change the oil. Every time you park. 

"Well I've never needed to use it before." "That's not how I was taught at driving school." "My father never uses it, he would know."

Since I am such a nice guy, I've decided to show you the relevant sections from five different automakers owner's manuals.

Ford Focus 2014

Chev Cruze 2014

Mazda 5 2014

Chrysler 200 2014

Nissan Versa 2014

So if you are going to say that it isn't necessary to use your park brake, your owner's manual disagrees with you. There is simply no excuse for the lack of safety you are putting you and others in by not setting the parking brake. This is what can happen when you don't set it:

The above picture is the result of the parking pawl failing to keep the jeep immobile. Is that what you want? Do you really want to have to explain that you caused an accident because you didn't know you were supposed set the parking brake?

Oh, never mind then.

Reference: http://www.driversedguru.com/driving-articles/car-auto-maintenance/always-set-the-parking-brake/