If you have to choose one over the other, it has to be vision surely?

Even ignoring various current issues with Lidar systems that aren’t fundamental limitations, large amounts of road infrastructure is just designed around vision and will continue to be for at least another few decades. Lidar just fundamentally can’t read signs, traffic lights or road markings in a reliable way.

Personally I don’t buy the argument that it has to be one or the other as Tesla have claimed, but between the two, vision is the only one that captures all the data sufficient to drive a car.

For one, no one is seriously contemplating a LIDAR-only system, the question is between camera+LIDAR or camera-only.

> Lidar just fundamentally can’t read signs, traffic lights or road markings in a reliable way.

Actually, given that basically every meaningful LIDAR on the market gives an "intensity" value for each return, in surprisingly many cases you could get this kind of imaging behavior from LIDAR so long as the point density is sufficient for the features you wish to capture (and point density, particularly in terms of points/sec/$, continues to improve at a pretty good rate). A lot of the features that go into making road signage visible to drivers (e.g. reflective lettering on signs, cats eye reflectors, etc) also result in good contrast in LIDAR intensity values.

> camera+LIDAR

It's like having 2 pilots instead of 1 pilot. If one pilot is unexpectedly defective (has a heart attack mid-flight), you still have the other pilot. Some errors between the 2 pilots aren't uncorrelated of course, but many of them are. So the chance of an at-fault crash goes from p and approaches p^2 in the best case. That's an unintuitively large improvement. Many laypeople's gut instinct would be more like p -> p/2 improvement from having 2 pilots (or 2 data streams in the case of camera+LIDAR).

In the camera+LIDAR case, you conceptually require AND(x.ok for all x) before you accelerate. If only one of those systems says there's a white truck in front of you, then you hit the brakes, instead of requiring both of them to flag it. False negatives are what you're trying to avoid because the confusion matrix shouldn't be equally weighted given the additional downside of a catastrophic crash. That's where two somewhat independent data streams becomes so powerful at reducing crashes, you really benefit from those ~uncorrelated errors.

Sorry if this is obvious, but are there actually any systems that "choose one over the other"? My impression's always been it was either vision + LIDAR, or vision alone. Are there any examples of LIDAR alone?

Roombas

Roomba (specifically the brand of the American company iRobot) only added lidar in 2025 [1]. Earliest Roombas navigated by touch (bumping into walls), and then by cameras.

But if you use "roomba" as a generic term for robot vacuum then yes, Chinese Ecovacs and Xiaomi introduced lidar-based robot vacuums in 2015 [2].

[1] https://www.theverge.com/news/627751/irobot-launches-eight-n...

[2] https://english.cw.com.tw/article/article.action?id=4542

> Earliest Roombas navigated by touch (bumping into walls)

My ex got a Roomba in the early 2010s and it gave me an irrational but everlasting disdain for the company.

They kept mentioning their "proprietary algorithm" like it was some amazing futuristic thing but watching that thing just bump into something and turn, bump into something else and turn, bump into something again and turn again, etc ... it made me hate that thing.

Now when my dog can't find her ball and starts senselessly roaming in all the wrong directions in a panic, I call it Roomba mode.

Neato XV-11 introduced lidar in 2010. Sadly they're no more.

I don't think they would be as well accepted into peoples homes if they had a mobile camera on it. Didn't they already leak peoples home mappings?

For full self driving sure but the more regular assisted driving with basic ‘knows where other cars are in relation to you and can break/turn/alarm to avoid collisions’ as well as adaptive cruise control lidar can manage well enough.

I think fsd should be both at minimum though. No reason to skimp on a niw inexpensive sensor that sees things vision alone doesn’t.