Roy's Razor: Your Litmus Test For Self-Driving

All words must have clear meaning, or no words do.

May 04, 2025

I’d like to say the most entertaining thing about living in Scottsdale is taking Waymos several days a week, but that would be a lie. The most entertaining thing about it is reading about self-driving cars while riding in the back of one.

My feed is filled with news and opinions about self-driving, and most of it is garbage. Apparently self-driving cars are already here, or will never happen. They’re also far safer than human drivers, or never will be. You can also buy one today, or you’ll never be able to.

It would be easy — at least from the backseat of an actual self-driving car like a Waymo — to say half these people are wrong. But that wouldn’t solve the actual problem: “self-driving” means different things to different people, which is why people seem to disagree about it so much.

Electricity doesn’t have that problem. I have power, or I don’t. My lights turn on, or they don’t. People can disagree over how to generate electricity, but no one says it can’t be generated.

We need a self-driving litmus test. Not a technical test, or debate over how it works. We need a self-driving litmus test because we need to know whether someone is talking about a real self-driving car, or something simpler, like the cars with driver assistance features people use everyday.

Besides, normal people don’t really care what things are called. We say we do, but we don’t. We care about what things do, and how well they do them.

So here’s a self-driving litmus test let’s call Roy’s Razor. It’s a simple test, as easy as flicking a light switch to check if my power is on:

Can I sleep in it?

That’s it. That’s the test. Pick a vehicle. Can you get in, pick a destination and safely go to sleep? If yes, it’s self-driving. If no, it’s not. Just like power: On. Or off.

Think about it. When you get in a taxi, the driver doesn’t ask you to drive. You get in the back. You can close your eyes. You can sleep in it. You don’t care who or what is driving. The whole point is that it’s not you. Not even a little bit.

The self-driving litmus test wasn’t my idea, it was my 81-year old mom Inga’s. She doesn’t know anything about coding or AI, but she knows a lot about straight talk, which makes her more of a self-driving expert than most of the talking heads out there. I was trying to #SonSplain the benefits of replacing her 2005 manual transmission Porsche with a Tesla like mine. She’s never owned a car with active cruise control or automatic emergency braking, so I was positive she would love the convenience of Full Self-Driving, which is what Tesla calls their best driver assistance feature.

“That all sounds very nice,” she said. “But can I lie down in the back and sleep in it?”

“Errrrrrrrr…no.”

“But,” she said with a sad puppy dog face, “I thought your Tesla was self-driving.”

“No, but—”

“Ooooooooo,” she cooed, “I thought you got the self-driving option.”

“You mean Full Self-Driving capability? Yes, I have that.”

“So…if I get that…can I sleep in it?”

“No, mom.”

“What about napping? Can I nap in it?”

“No.”

“A nap isn’t quite as long as sleeping,” she said. “Maybe just a little nap? Fifteen minutes?”

“Not unless someone else is behind the wheel and-”

“How funny,” she frowned. “Someone should put a sticker on all these cars in the showroom. A sticker that says DRIVE, NAP, or SLEEP. I would pay a little if I could nap, and more if I could sleep. Elon seems very smart, and I like his mother. She and I have similar style, you know. I think we would get along. You should send him an e-mail-”

“I will, mom.”

“-and ask him when I can sleep in it.”

_______________________________

But Teslas aren’t the only cars people (wrongly) think are self-driving. “Self-driving” cars you have to drive are growing in popularity, as I learn every time I go to a party and someone asks me what I’m investing in. As soon as I say “self-driving cars” someone else says their car already has that. Last week it was a BMW. And a Mercedes. And a Volvo. These cars all have some kind of driver assistance technology. It might just be cruise control. It might include some kind of basic lane keeping.

But can you safely sleep in them? Of course not, unless you’re parked, or someone else is behind the wheel.

That’s the thing. “Self-driving” has to mean you can sleep in it, because if it doesn’t, what will we call self-driving vehicles that will let you close your eyes?

So remember, my friends. Don’t believe the hype. Use #RoysRazor. If you can’t sleep in it, it’s not self-driving.

And for the record, I fall asleep in the back of Waymos all the time. Just like I would in any other taxi. I love it. Why would I give that up? I’m getting too old to drive myself in traffic. I’d rather scroll through my newsfeed, or call my mom. She still doesn’t believe me when I tell her where I’m calling from.

Alex Roy is a General Partner at NIVC, co-founder of Johnson & Roy Advisors, The Drive, and Autonocast, Chairman Emeritus of The Moth, author of The Driver, and has set 8 Cannonball Run endurance driving records.