Cadillac's Safety Alert Seat has two small motors in the driver's seat, one on the right side and one on the left side. Both are toward the back of the seat. These motors are connected to Cadillac's electronic safety systems, and when a problem is detected, one or both motors vibrate.
When Ray Keifer, General Motors active safety technical fellow and the inventor of this seat, was asked where the driver would feel these vibrations, he quite diplomatically replied, "the upper thigh." Not that a playground full of third-graders is a better judge of human anatomy than a scientist, but pretty much everyone is going to agree with the kids that what we're talking about here is the butt. You're going to feel it on your butt.
Speaking of science, what the seat actually uses is called haptic feedback. Keifer explained that there are lots of ways to get information to our brains, like our senses of sight, smell, and hearing. "Haptic" is related to our sense of touch. "It's also used to describe kinetic sensations; it could be the whole vehicle jerking," said Keifer. "Any type of vibration is a haptic alert."
The vibrations signal the driver that something is going wrong, or more likely, is about to go wrong if he or she doesn't change something soon. Take the Cadillac lane departure warning feature, for instance. "If you're drifting in your lane without using the turn signal, it triggers the lane departure warning," said Keifer. "The driver feels three quick pulses on the left side of the seat. It's similar to a rumble strip feeling, very intuitive."
See? It makes way more sense than you thought, right?