You're making one mistake here. The "if" component. It won't be rolled out if it doesn't work, and if it didn't work they wouldn't be putting it on 2017 models. The way the auto industry works cars are set for production several model years ahead of time, and it can take easily 10 years to get a car from design to showroom. GM isn't just starting with Cadillac because of expense; it's also marketing. It's not as if a Silverado isn't already $50k, or a Corvette isn't $80k. Their strategy is about building Cadillac as a luxury car and then letting the proles who drive Chevys and Buicks have a piece of the action, too.Assuming that works, it will be at least a year, possibly two until most of the GM fleet has the same kit of sensors, and they will definitely start at the higher end because this tech ain't cheap just yet. So we're talking about 2018 or 2019 for mass-scale production at the very least.