Your car has long been a sanctuary on wheels but that won't be true for much longer. Car manufacturers will soon be adding radar and lasers inside the cabin to monitor who you are and what you do, and that will mean even more of your personal habits being tracked.
Millimeter-wave radar is perhaps the most intriguing in-car detection tech. The apparatus itself can be compact because its frequency is so high and therefore its emitted wavelength is short. I've seen several examples about the size of a card deck that could easily be mounted on the headliner of a car and look down at its cabin. Texas Instruments has been showing carmakers how that view can not only detect objects in the vehicle but also classify them as an adult, a child or even a dog.
Mount that same radar inside a seat and you can detect small movements in the driver's body that, with enough computing power, can be translated into a reading of respiration rate.
Startup Caaresys imagines its radar-based system monitoring the respiration and heart rates of everyone in the car, with a particular focus on sensing a child that might be hidden from view in the back and potentially left behind in the car.