Excerpt:
"Let’s start with what’s styled “speed limit assistance technology.”

It works by continuously keeping track of exactly how fast you’re driving at any given time and exactly what the speed limit is at the same time. It works via the GPS “technology” all new vehicles have that is aware of the vehicle’s speed as you’re driving that is then correlated with data about the road you’re driving on; specifically, what the speed limit is on that road. Which it knows because speed limits are part of what’s mapped by the GPS.

The two bits of data are compared and if you are driving faster than whatever the speed limit is, the car “assists” you via an icon built into the dash display that looks just like a speed limit sign – the number displayed being the speed limit of the road you’re driving on – that shifts from the white background with black lettering of the actual speed limit sign to angry red and flashing, often accompanied by a tone.

You know, like the kind used to train a puppy.

In Europe, where this “technology” has already been mandated, the “assistance” is more forceful. If the driver exceeds the speed limit, the car slows down. The accelerator pedal becomes harder to depress – or it pushes back. The driver can (for now) push down harder, to override the “assistance” – but the relevant fact is that the driver can be overridden by this “technology.”

In order to understand the how of that it is necessary to understand that pretty much all vehicles made since at least a decade ago have computer-controlled accelerator pedals.

In the past, the accelerator pedal was connected to a cable and the cable pulled on the throttle when the driver pushed down on the accelerator pedal, giving the driver absolute control over engine acceleration. Push down on the accelerator and the engine would speed up, thereby causing the car to speed up.

But about a decade ago, it became common for new vehicles to have what’s called drive-by-wire throttle control. There is still an accelerator pedal – but it no longer controls the acceleration of the engine.

The computer that controls the operation of the engine does."