How to rig a car wheel. I don't find the add single driver option I am following different tutorials about how to rig a car wheel and they all show in some moment the option to "add a single driver" 



but this option does not appear to me.



Does anybody knows why? Maybe a Blender update?
Thanks in advance
Yes, it's an UI update that happened between 2.77 and 2.74.

The workflow initially was to assign an "empty" driver and then define it in the graph editor. Nowdays it's provided an option to set a driver based on a picked object.

You can obtain the same result shown in your video by choosing "Manually Create Later (Single)" option in the driver menu.