Doesn't it really frustating when everything from event to positioning is good but when you testing the collisions, it doesn't work? Well... I know how you feel... This tutorial will teach you how to fix it easily.
1) Make sure the object you want to be collided with is in the same layer as the collider.
Icon by Freepik [http://bit.ly/icon-Car-Collide-by-Fre...]