Tesla pushes into self-driving cars is garnering attention because of its reputation — deserved or not — as being the most technologically advanced car maker on the planet.
Conventional all wheel drive vehicles distribute power to the wheels from a single engine driving a complex mechanical transmission system. By contrast, Dual Motor Model S has a motor on each axle, digitally and independently controlling torque to the front and rear wheels.
It's not clear exactly when everyday Model S owners will get their turn, but it's important to temper expectations. The technology isn't really a peek at a future dominated by self-driving cars... at least, not yet. You'll still need to flick the turn signal to pass cars (to indicate intent and absolve Tesla of liability), and the additions won't help much when you're stuck in city traffic.
The company has been clear that it's not ready to let the cars take over all of the driving decisions just yet. To engage the autopassing function, for example, drivers will need to manually use the turn signal.