Other contributors have said "What are lariat used for?" is the same question as "What is a Lariat?" If you believe that these are not asking the same thing and should be answered differently, click here
A lariat is a special way of tying a rope so that it forms an adjustable loop at the end. The rope is thrown over the neck or leg of an animal and then pulled tight to stop the animal from running....
Since you put this in cars and vehicles I am going to say it's a Ford f150 Lariat with all the options, then pick one of everything from the accessory aisle at the auto parts store and stick it on...