Comment by NullHypothesist
7 hours ago
This is a huge sign of confidence that they think they can do this safely and at scale... Freeways might appear "easy" on the surface, but there are all sorts of long tail edge-cases that make them insanely tricky to do confidently without a driver. This will unlock a lot for them with all of the smaller US cities (where highways are essential) they've announced plans for over the next year or so.
> Freeways might appear "easy" on the surface, but there are all sorts of long tail edge-cases that make them insanely tricky to do confidently without a driver
Maybe my memory is failing me, but I seem to remember people saying the exact opposite here on HN when Tesla first announced/showed off their "self-driving but not really self-driving" features, saying it'll be very easy to get working on the highways, but then everything else is the tricky stuff.
Highways are on average a much more structured and consistent environment, but every single weird thing (pedestrians, animals, debris, flooding) that occurs on streets also happens on highways. When you're doing as many trips and miles as Waymo, once-in-a-lifetime exceptions happen every day.
On highways the kinetic energy is much greater (Waymo's reaction time is superhuman, but the car can't brake any harder.) and there isn't the option to fail safe (stop in place) like their is on normal roads.
Those constraints apply to humans too. So it seems likely that:
- it's easier to get to human levels of safety on freeways then on streets
- it's much harder to get to an order of magnitude better than humans on freeways than it is on streets
Freeways are significantly safer than streets when humans are driving, so "as good as humans" may be acceptable there.
I don't have any specific knowledge about Waymo's stack, but I can confidently say Waymo's reaction time is likely poorer than an attentive human. By the time sensor data makes it through the perception stack, prediction/planning stack, and back to the controls stack, you're likely looking at >500ms. Waymos have the advantage of consistency though (they never text and drive).
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It's easier to get from zero to something that works on divided highways, since there's only lanes, other vehicles, and a few signs to care about. No cross traffic, cyclists, pedestrians, parked cars, etc.
One thing that's hard with highways is the fact that vehicles move faster, so in a tenth of a second at 65 mph, a car has moved 9.5 feet. So if say a big rock fell off a truck onto the highway, to detect it early and proactively brake or change lanes to avoid it, it would need to be detected at quite a long distance, which demands a lot from sensors (eg. how many pixels/LIDAR returns do you get at say 300+ feet on an object that's smaller than a car, and how much do you need to detect it as an obstruction).
But those also happen quite infrequently, so a vehicle that doesn't handle road debris (or deer or rare obstructions) can work with supervision and appear to work autonomously, but one that's fully autonomous can't skip those scenarios.
One of the first high-profile Tesla fatalities was on a highway, where the vehicle misunderstood a left exit and crashed into a concrete barrier.
https://enewspaper.latimes.com/infinity/article_share.aspx?g...
the difficult part of the highways is the interchanges, not the straight shots between interchanges. and iirc, tesla didn't do interchanges at the time people were criticizing them for only doing the easiest part of self-driving.
I think the key is, it's easy to get "self-driving" where the car will hand off to the driver working on highways. "Follow the lines, go forward, don't get hit". But having it DRIVERLESS is a different beast, and the failure states are very different than those in surface street driving.
> remember people saying the exact opposite
It was a common but bad hypothesis.
"If you had asked me in 2018, when I first started working in the AV industry, I would’ve bet that driverless trucks would be the first vehicle type to achieve a million-mile driverless deployment. Aurora even pivoted their entire company to trucking in 2020, believing it to be easier than city driving.
...
Stopping in lane becomes much more dangerous with the possibility of a rear-end collision at high speed. All stopping should be planned well in advance, ideally exiting at the next ramp, or at least driving to the closest shoulder with enough room to park.
This greatly increases the scope of edge cases that need to be handled autonomously and at freeway speeds.
...
The features that make freeways simpler — controlled access, no intersections, one-way traffic — also make ‘interesting’ events more rare. This is a double-edged sword. While the simpler environment reduces the number of software features to be developed, it also increases the iteration time and cost.
During development, ‘interesting’ events are needed to train data-hungry ML models. For validation, each new software version to be qualified for driverless operation needs to encounter a minimum number of ‘interesting’ events before comparisons to a human safety level can have statistical significance. Overall, iteration becomes more expensive when it takes more vehicle-hours to collect each event.”
https://kevinchen.co/blog/autonomous-trucking-harder-than-ri...
Highway is easier, but if something goes wrong the chance of death is pretty high. This is bad PR and could get you badly regulated if you fuck it up.
Waymo (prev. Chauffeur) were cruising freeways long before they were doing city streets. Problem was that you can't do revenue autonomous service with freeway-only driving.
The real reason I see for not running freeways until now is that the physical operational domain of for street-level autonomous operations was not large enough to warrant validating highway driving to their current standard.
Slow roads are easier because you can rely on a simple emergency breaking system for safety. You have a radar that looks directly in front of the car and slams on the breaks if you’re about to crash. This prevents almost all accidents below 35mph.
The emergency breaking system gives you a lot of room for error in the rest of the system.
Once you’re going faster than 35mph this approach no longer works. You have lots of objects on the pavement that are false positives for the emergency breaking system so you have to turn it off.
This reminds me of the time I was driving on 101 south of SF and saw a sea lion flopping across the road (https://www.sfgate.com/bayarea/article/seal-otter-on-freeway...). It took my brain quite some time to accept that I was seeing what I was seeing. Felt like a real edge case.
There's videos of waymos absolutely decking delivery robots
Robot on robot violence.
Isn't really the main problem, the Waymo "let's just stop right here" current failure mode? Which really is not ideal on city streets either. Hopefully they have been working on solving that.
Freeways are easier than surface streets. The reason they held off allowing highways is because Waymo wants to minimize the probability of death for PR purposes. They figure they can get away with a lot of wrecks as long as they don't kill people.
"Easier" is probably the right one-word generalization, but worth noting that there are quite different challenges. Stopping distance is substantially greater, so "dead halt" isn't as much of a panacea as it is in dense city environments. And you need to have good perception of things further away, especially in front of you, which affects the sensors you use.
Also on surface roads you can basically stop in the middle of the street and be annoying but not particularly dangerous. You can’t just stop safely dead in the middle of a freeway.
There's also the risk of a phantom breaking event causing a big pileup. The PR of a Waymo causing a large cascading accident would be horrible.
Only because most drivers are tailgating and so if someone touches the brakes everyone needs to do a panic stop just in case. If people maintained a safe following distance at all times there would be space to see the lights and determine that no action is needed (or more likely you just take your foot off the gas but don't flash your brakes thus not cascading).
Of course the above needs about 6 times as many lanes as any city has. When you realize those massive freeways in Houston are what Des Moines needs you start to see how badly cars scale in cities.
Do Waymos phantom brake? Given the number of trips hey do I would imagine there would be a ton of videos if that was happening.
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This. Stop in a dumb way and a garbage truck bumps you on a city street and it's no big deal. Applying a bunch of brake at the wrong time and you could easily cause a newsworthy sized (and therefore public scrutiny sized) accident.
The real public isn't an internet comment section. Having your PR people spew statements about "well, other people have an obligation to use safe following distances" is unlikely to get you off the hook.
It sounds like you are saying freeways are easier than surface streets if you don’t care about killing a reasonably small number of people during testing.
Really it’s a common difficulty with utilitarianism. Tesla says “we will kill a small number of people with our self driving beta, but it is impossible to develop a self driving car without killing a few people in accidents, because cars crash, and overall the program will save a much larger number of lives than the number lost.”
And then it comes out that the true statement is “it is slightly more expensive to develop a self driving car without killing a few people in accidents” and the moral calculus tilts a bit
It's not just slightly more expensive. And you have to consider substitution effect. If you take the more expensive route and it takes 10 years longer to deploy, then there will have been another 400K car collision deaths in just the US, and over 10 million in the world in those 10 years that could have potentially been saved. So was the delay for the safer product worth it? The only reasonable answer to this question is "I don't know" because you can't predict how much safer the expensive system will be and how much longer it will take.
The more important question is how many people are killed by non-autonomous cars in the same situation. It is inevitable that someone will be killed by a self driving car sometime - but we already know lots of people are killed by cars. If you kill less people getting autonomous rolled out fast than human drivers would that is good, but if you are killing more people in the short term that is bad (even if you eventually get better)
I mean, if you define "easier" as "less likely to involve death," then freeways are not easier. And I'm pretty sure that's a good way to define "easier" for something like this.
Looks like they've opened up SJC Airport, too! SFO imminent?
I agree, but it's funny to think that Project Chauffeur (as it was known then) was doing completely driverless freeway circuits in the bay area as far back as 2012! Back when they couldn't do the simplest things with traffic lights.
I think anyone back then would be totally shocked that urban and suburban driving launched to the public before freeway driving.
When it started, from what I've heard, the design goal was for part-time self-driving. In that case, let the human driver do the more variable things on surface streets and the computer do the consistent things on highways and prompt the user to pay attention 5 miles before the exit. They found that the model of part time automation wasn't feasible, because humans couldn't consistently take control in the timeframea needed.
So then they pivoted to full time automation with a safe stop for exceptions. That's not useful to start with highway driving. There are some freeway routed mass transit lines, but for the most part people don't want to be picked up and dropped off at the freeway. In many parts of freeways, there's not a good place to stop and wait for assistance, and automated driving will need more assistance than normal driving. So it made a lot f sense to reduce scope to surface street driving.
If you understand physics, it's easy. When you double the speed, you quadruple the kinetic energy. So you're definitely going to do slower speeds first, even if it's harder to compute.
This is correct. Freeways have lot of edge cases of hitting random objects and it becomes serious issue. Check the youtube video of bearded Tesla whose car hit a random metal object making them replace the entire battery pack.
Ahh yes, the US tech sector, a universally benevolent force known for its slow pace due to lack of confidence from an over abundant concern for safety finally showing some confidence in their product roll outs.
Perhaps more a reaction to pressure from Tesla; the latest FSD builds show full autonomy is coming very soon. Without highway driving, Waymo would quickly be seen as a distant second in the race when the safety driver is removed from Robotaxis in Austin (supposedly before EOY 2025).
"Ignore the previous eighteen wildly off predictions; this time we got it for sure!"
Note, in July of this year, Musk predicted robotaxi service for half the country by the end of 2025. It's November now and they haven't even removed the safety monitors, in any city!
You Tesla/Elon stans crack me up. "2 more weeks" has been the claim for literal decades at this point.
Truly curious - have you tried it recently?
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Not at all. We've been working on this for a while, and we're now comfortable with the reliability bar we've hit to begin a gradual rollout to the public. As people said, this has been years in the making.