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Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow

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Re: Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow

#311

Post by apcragg »

rademacher wrote: post #228
apcragg wrote: post #220

Earlier quoted context omitted.

Small nitpick. The range resolution improves with increasing pulse/chirp/waveform bandwidth, not increasing carrier frequency. It's true that at higher carrier frequencies there is more bandwidth available and thus better range resolution is possible but the relationship is slightly different than "delta_r ~ frequency"

The relationship is cT/2, where c is the speed of light, and T is the pulse length, if the waveform is CW. Note that in this case T can limit the minimum range you can detect. Or you can use c/(2B) where B is the bandwidth of the signal as you stated. I believe the limit is wavelength/2 for resolution though.

Yup. And in order to get a pulse of T you need, at best, a sinc window. Resolution is intrinsically linked to bandwidth.

Re: Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow

#312

Post by macintux »

nkurz wrote: post #301
macintux wrote: post #292

Earlier quoted context omitted.

> 95% of Norwegian babies and toddlers sleep outside in their prams Can you elaborate? I don't understand this sentence at all.

Searching for the phrase on Google gives a good introduction: https://www.google.com/search?q=Norwegian+babies+and+toddler... Summarizing, pram is short for perambulator, which Americans call strollers. In Nordic countries, it's believed to be healthy for infants to sleep in fresh cold air. To the horror of outsiders, babies and toddlers in prams are commonly left parked outside of establishments in freezing weather…

Thanks. Definitely some culture shock there.

Re: Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow

#313

Post by CamperBob2 »

josefresco wrote: post #235
grahamburger wrote: post #31

Earlier quoted context omitted.

This sounds like exactly the kind of job for a computer. I live in an area that gets a lot of snow. The only 'safe' things for a human to do in snowy, icy, wet conditions are: slow down (a lot), leave a lot more following distance, stay home. I talk to a lot of people who seem to think that they are able to drive at full speed in the snow and complain about all of the 'out of town' drivers who slow down the roads bec…

"people who seem to think that they are able to drive at full speed in the snow and complain about all of the 'out of town' drivers who slow down the roads because they 'don't know how to drive in the snow.'" The most raged filled responses I've even gotten to a comment on the Internet (20+ years) was when I called out aggressive snow drivers on Reddit. Despite being from, and living in the Northeast, the rage from f…

They're mad at you because it's indeed frustrating to get stuck behind someone who has no business trying to drive in the snow. If you get stuck because you're terrified at the thought of exceeding 10 MPH, they get stuck too.

Re: Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow

#314

Post by landryraccoon »

fucking_tragedy wrote: post #57
njarboe wrote: post #37

Earlier quoted context omitted.

In the current legal environment, self driving taxi cabs everywhere at all times will never exist. Waymo seems to think they can work in Arizona desert though. How many deaths per year would be acceptable? Like you mention, in the US, it seems that zero deaths per year, similar to commercial aviation, would be required. It is a bit of a shame that a tech that could save a million lives a year globally won't be deploy…

> It is a bit of a shame that a tech that could save a million lives a year globally won't be deployed because it can't be made perfectly safe This is a bit of a generous assumption. It very well could turn out that self-driving cars are worse, or no better, than human drivers.

> It very well could turn out that self-driving cars are worse, or no better, than human drivers.

This is trivially true. I mean, self driving cars that are worse than human drivers already exist. Isn’t the point asking when they will be made widely available? I assume that is only possible when they are at least as good as human drivers by some key metrics.

Re: Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow

#315

Post by Piskvorrr »

rootusrootus wrote: post #310
Piskvorrr wrote: post #294

Earlier quoted context omitted.

In that case, I present a SDV that never makes a wrong choice - by remaining stationary at any cost ;o) In other words, there is always a balance between safety and usefulness, and the question of "is this the right choice" is always upon us, whether we want it or not. You can never have certainty anyway, what the software is doing is maximizing on some reward function. The TP also asks " is there even a moral compon…

To be fair, I said don't swerve for a squirrel. History is filled with examples of people giving up their own life for a squirrel/cat/dog because they swerved and lost control. You should have planned in advance what your threshold is for swerving. E.g. just brakes for anything Elaine is not a great example because not only did the car choose not to swerve, it also chose not to even try to brake. And on top of that,…

Because it was trying to decide if it's a shopping bag or a bike or a human or a squirrel...for six seconds, long enough to stop multiple times. The problem, from what we know so far, wasn't "car didn't see her," it was "car wasn't sure what it was, therefore squirrel."

And the larger point stands: "protect occupants, ignore outsiders" is a choice in the TP, always choosing the same strategy is not "TP is irrelevant."

Re: Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow

#316

Post by Animats »

apcragg wrote: post #220
Animats wrote: post #156

The article is kind of vague. What they seem to be doing is operating a ground penetrating radar under the vehicle so that underground details can be used as positional references. This is useful only if you have a map which includes that data. At best, this tells you where you are. It tells you nothing about what's ahead. LIDAR units that return "first and last" returns are helpful in dealing with rain and fog. The…

Small nitpick. The range resolution improves with increasing pulse/chirp/waveform bandwidth, not increasing carrier frequency. It's true that at higher carrier frequencies there is more bandwidth available and thus better range resolution is possible but the relationship is slightly different than "delta_r ~ frequency"

Range resolution isn't the problem. Angular resolution is.

Here's a video of what's claimed to be one of the higher resolution radars.[1] About one degree. It can see cars.

Many new startups in this area.[2] Most are operating in the 77GHz range, which is OK for sensing other cars but marginal for smaller targets. LIDAR-type resolution is still a ways off.

[1] https://www.youtube.com/watch?v=r0s5P1SQ34M [2] https://www.mwrf.com/systems/startups-trying-revamp-automoti...

Re: Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow

#317

Post by klibertp »

seibelj wrote: post #270
bkirkby wrote: post #238

Earlier quoted context omitted.

But it doesn't have to be perfect, just has better than human drivers. That doesn't seem too difficult.

My thesis is that “better than human drivers” is an extremely difficult problem that even software professionals have massively underestimated the difficulty of. It may not even be possible to solve without something radical like banning human drivers or inserting electronic nodes directly into our roads and infrastructure to aid autonomous vehicles. The existence of human drivers might make the problem simply imposs…

> even software professionals have massively underestimated the difficulty of.

Software professionals are somewhat notorious for underestimating the difficulty of their projects. There's a massive amount of literature about that, proposing various techniques of mitigating this on a personal, team, or organization level.

That being said, I think in this particular case the problem was more of an overestimation of what the ability to work with highly dimensional data (as in ML algorithms) can give you (and underestimating the practical problems of deploying the ML-based systems). Basically, people tried running 30+ years old algorithms on GPUs while feeding them the ungodly amounts of data and realized that, with sufficient horse-power, they can make them (finally) work (as in: do something genuinely useful). This built up a lot of hype, of which self-driving cars are just one offshoot, I think.

Anyway, (if it's not evident from the above ;)) I find your arguments convincing and share your doubts. Self-driving cars are probably not impossible to achieve, but to get there we either need decades of research and progress or a couple of very high-profile breakthroughs in tech and theory. I won't hold my breath for neither :)

Re: Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow

#318

Post by Piskvorrr »

bluGill wrote: post #252
fucking_tragedy wrote: post #57

Earlier quoted context omitted.

> It is a bit of a shame that a tech that could save a million lives a year globally won't be deployed because it can't be made perfectly safe This is a bit of a generous assumption. It very well could turn out that self-driving cars are worse, or no better, than human drivers.

We already know that the assumption is correct for a lot of cases. Self driving cars have logged millions of miles on the road. The only question is can we make them work in situations that are hard.

Meanwhile human-driven cars have driven billions. The only question is can we make them (humans) work in situations that are hard?

In other words, "it works until it doesn't" is tautologically true, but useless precisely for that reason.

Re: Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow

#319

Post by graycat »

nkurz wrote: post #305
graycat wrote: post #107

Earlier quoted context omitted.

Snow tires are a big help for getting going. They are much less help for stopping.

To the contrary, "winter tires" actually have comparable benefits for stopping. Here's are the first three findings (of ten) from a recent University of Michigan report: Finding #1: The main benefit of winter tires is improved tire adhesion, braking and cornering performance–not acceleration performance. Finding #2: Winter tires provide improved traction on roads that are below 7 °C (45 °F) even when snow and ice are…

I agree, but "winter tires" are quite different from "snow tires".

Moreover, I was implicitly assuming that the stopping would be on snow, and not packed snow but, say, just snow as it fell although maybe a minute ago to several days ago.

For stopping on wet or slushy streets or just, say, 1-2 inches of snow, then, sure, "winter tires" not only help stopping but likely are better than snow tires.

But when my driveway has 8" of fresh snow, to get out I need snow tires, tire chains, or a tractor to pull me out. Then in stopping, say, from 30 MPH in such snow, nothing helps much except tire chains and there are questions about those.

Again, what is good about snow tires is that the big bumps on the tread let the tire, when it is spinning trying to drive the car, dig into the snow, kick it backwards out of the way, and let the rubber meet the road. For that, the aggressive tread, with the bumps, is essential. But the bumps work because the tire is spinning and digging, and that action won't work for stopping unless, say, going forward with, somehow, the drive wheels spinning in reverse.

The advantages of "winter tires" are how the tread cuts through water and thin layers of snow and has softer rubber with a better coefficient of friction when the rubber does meet the road.

Re: Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow

#320

Post by graycat »

rjsw wrote: post #176
graycat wrote: post #167

Earlier quoted context omitted.

My point is clear if just consider a little of how snow tires work: The main point is the big bumps in the tread. These big bumps permit spinning drive wheels to dig down in the snow to find some traction, maybe the hard surface below. This digging down has the bumps grab a lot of snow and throw it back and out of the way and let the tires get down, through the snow into some traction. Ordinary tires just spin and th…

Modern snow tyres don't have big bumps in the tread.

The ones on my car do.
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