What is a driverless car?

Driverless cars will be here before you expect it…or so we often hear. But that phrase can be confusing and misleading. Between bombastic predictions by automotive CEOs and erratic use of the term by the media and others, a clear understanding of when this technology is coming can be hard to come by. So let’s unpack it. This article will clarify what I mean when I use the term driverless car so that you know what I mean when I discuss the timeline for and implications of this technology elsewhere.

So what do I mean when I say driverless car? For starters I use the terms self-driving, autonomous, driverless interchangeably. Some in the field have tried to distinguish between these terms, but these distinctions have not been widely adopted and I don’t find them particularly useful. The Society for Safety Engineers (SAE), on the other hand, has provided a very helpful and widely cited definition for levels of autonomy.

SAE Levels of Automation
Source: SAE International, J3016

Practically all cars on the road today qualify as SAE level 1 with nearly ubiquitous anti-lock brake systems and cruise control. Automakers like Tesla and GM have already commercially released vehicles that achieve Level 2 automation. These vehicles can operate the pedals and steering wheel in certain conditions.

But, this isn’t what I’m referring to when I say driverless car because, while these vehicles do offer benefits (especially safety benefits), they will not cause a transportation revolution. They won’t dramatically impact our urban form or our urban footprint. They won’t upend the transportation sector. And they won’t transform the transportation experience.

The technology that WILL cause this revolution is somewhere above Level 4 automation. It is the point at which we can safely jettison those features of a car that allow people to control them. Once they no longer need a driver (or an attentive passenger), they are driverless cars. To be clear, I don’t believe we need every vehicle to be capable of operating in every condition, on every road, in every city and state. That is Level 5 autonomy.  But we do need a fleet of vehicles that are collectively capable of achieving this so that the vast majority of trip needs can be met by a driverless car.

So, when I say autonomous or driverless or self-driving car, I mean a car that doesn’t need or expect a person to operate it at any point in a trip. I mean a car that doesn’t care if its passenger is sleeping, reading or playing with a phone.