Engineers at Ford are working hard toward a breakthrough: A car that runs on tears! Okay, maybe not, but they really should be. Why? Because people cry in cars, a lot! Whether it's a sad song playing on the radio, passing a cemetary where a loved one is buried, or simply releasing the stress of a long, hard day, the car is one of the few places that offer the privacy and intimacy necessary for a good cry.

So what is it about cars that allow us to be so vulnerable? How, while surrounded by windows on all sides, do we manage to shroud ourselves in the illusion of privacy? On today's show we talk with psychologists and self professed car-cryers to explore this very phenomenon.