I’d like to know how the sensor will ensure the driver is sober when they’re the responsible designated driver trying to bring home a carload full of plastered friends… I have at least one friend that I know would think it’s hilarious (at the time) if he was a drunk passenger and could make the car stop by breathing on the driver etc.

A camera could focus on the drivers seat, but I feel like that would be lousy at this sort of thing… Is the driver drunk, is he shivering because it’s cold out? Does he have a cold, or even just a lazy eye or suffer from tremors of some sort?

Any sort of breath or touch sensor is going to need to be smart enough to distinguish between driver & passengers. And if it’s a touch sensor in the steering wheel does that mean no more gloves on a cold winter day?