How the Cadillac Safety Alert Seat Works

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?

Besides the rumble strip simulation for lane departure, the Safety Alert Seat works with the front and rear park assist sensors, the rear cross-traffic alert and a new backing warning feature for when you're backing up at higher speeds. The car will not only shake your rump to tell you to watch out behind you, it'll apply the brakes for you if you're not quick enough on the pedal.

You may have seen the commercial for the cross-traffic alert, where someone is backing out of a parking space with huge SUVs on either side. The driver can't see a thing, but the Cadillac has radar looking up and down the aisle. If it picks up another vehicle on the right, the right side of the seat vibrates. It also puts the information in the center console, just in case your butt isn't smart enough to pick up on the haptic warning. (Haptic! It's the word of the day!)

What would possess a man to design a system to shake the rumps of Cadillac owners while they drive? Keifer said he was inspired by the tactile warnings used by the visual and hearing impaired. "Some of our drivers are hearing impaired, or beeps can't be heard because of background noise," he said. "In the course of my research, I became aware that some companies were using vibration for navigation purposes to signal left vs. right. The idea came to me to use it for alerting the driver to potential crashes."

Having a nearly silent alert serves another purpose, too: Most people turn off safety systems when they get annoying. If you've ever driven a car with a park assist system, you know that the beeping inside the car can get a bit shrill. You may find yourself screaming, "Shut up! Shut up! Shut up!" at the poor car, which is really just trying to help you. A quick, quiet vibration is less likely to bug you, according to Keifer.

"It also provides privacy benefits," said Keifer. "Do the passengers in the car really need to know every time you drift out of the lane?" No, they do not. Nor do they need to comment on one's challenges with parallel parking. "Things like lane departure and park assist beeps happen daily," Keifer added. "Annoyance is a big deal. We want to keep people from turning the safety systems off."