Cruise control—which keeps a vehicle at a constant speed—has been around for decades. But a recent upgrade could spark a progression of advances that might finally lead to the long-envisioned car that drives itself.
With standard cruise control, a driver sets a desired speed. The engine controller opens the throttle to accelerate the car or closes it to slow the car using engine drag. A few enhanced systems can also gently apply the brakes if the drag is insufficient—for example, when the car is heading down a steep hill.