The progression of typically mechanical vehicle systems toward electronic control has been—for the average consumer, anyway—one of the less-visible technological shifts of the last 50 years. Throttle-by-wire systems that possess no mechanical link between the pedal and the engine have been around for decades, and have helped enable precision cruise control, stability control, and pre-crash safety systems that modulate engine torque regardless of what the driver’s foot is up to. Most car owners don’t know or care about such relative minutiae, and typically, the worst that can happen if it fails is that you just won’t go anywhere.

Steer-by-wire—a newer and rarer technology debuted by Infiniti in the Q50 sedan in 2014—allows for tunable feel and responsiveness with, again, no physical link between the steering wheel and the spinning rubber at the front corners. On the consumer freak-out scale between “NBD” and “WTF?” this system leans perilously close to the latter; after all, visions of steering wheels spinning cartoonishly from lock to lock with no effect could give anyone a fright. But Infiniti’s equally innovative mechanical backup system—which, at last check a year ago, had never been activated in actual use—ensures you retain control even if some digital gremlin pees on your steering sensors. No failures, no problem.

Which brings us to brake-by-wire. This idea has been lurking since the dawn of modern electrified cars in the early 2000s—most notably in the Toyota Prius, but also in GM, Ford, and Honda hybrids. It helps considerably with regenerative braking, where the motors take first crack at slowing the vehicle in order to pump electricity back into the batteries (unless the mechanical brakes are needed for more aggressive braking). Because it’s an even scarier proposition than steer-by-wire, the tech is advancing more slowly. Formula One race cars have had it since 2014, but beyond them, it’s mostly been the domain of a few hybrid models.

In fact, Audi’s new E-tron is the first fully electric vehicle to include brake-by-wire technology...and even there, it comes with an asterisk. While true brake-by-wire systems would use electronically controlled brake calipers instead of hydraulic pressure, Audi’s system is electrohydraulic. There’s still no mechanical link between pedal and pad—save for a redundant backup we’ll discuss shortly—but the actuator on the business end of the brakes remain hydraulic; it's just controlled by the computer in response to the amount of pressure the driver lays on the pedal.