[xya3453]

Apparently the driver of the Tesla didn't have time to react to the firetruck as their field of view was obscured by a large pick-up truck that changed lanes seconds beforehand.

If Tesla's autopilot can't detect upcoming stationary objects, it should in the very least keep enough distance between itself and the vehicle ahead in order to allow the human at the wheel to have an unobscured view of the road ahead.

[irq-1]

Autopilot quitting when it's too difficult, and expecting a human to jump-in at the last second is a stupid plan. Tesla needs to fix their attitude to failure and take the blame if autopilot gives up.

[ajmurmann]

If in the very least the autopilot could ring an alarm when it gives up. It seems like the autopilot in this case didn't know it had given up. The engineers had given up...

[nmeofthestate]

According to the article, a stopped truck is in the same class of objects as an overhead sign, so a lot of false alarms would be going off if this wasn't also fixed.

[Someone1234]

Which is odd within itself, my Subaru which uses optical (visual) sensors can detect stationary vehicles fine even at highway speeds.

Does Tesla's system have no optical sensors?

[sli]

It does have an alarm when it's about to avoid an obstacle (and it's actually a pretty cool noise, if you ask me), not sure why it wouldn't have one for this scenario as well.

[tbirrell]

I was in a crash some time ago where the car in front of me jumped out of the way because the guy in front of him was at a dead stop. I can understand why this is an issue for the autopilot. I mean, it's an issue for humans too. It is simply infeasible to drive on a highway in such a way you account for stationary objects in a lane. If we did that, we would never get above 5mph.

[mhermher]

The car in front needs to react earlier. He/she should have seen it early enough to make it safe, no?

[toast0]

In the cases presented, the car in front reacted in time to make it safe for that car, but they probably had a less obstructed view. It's not the car in front's responsibility for the car behind to follow at a safe distance.

[mrguyorama]

It is your responsibility as a driver to maintain a safe distance behind the car you are following. The car in front of you should be able to spontaneously turn into a brick wall, and you should have enough space to stop before hitting it

[tbirrell]

That is completely unrealistic. If I had brand new tires on a dry, straight, road. That's still something like 15-20 car lengths (~160-180) feet.

[sangnoir]

> That is completely unrealistic.

Why is it unrealistic, besides the fact that you're following too close behind? If your line-of-sight is shorter than your braking distance, you are driving wrong.

[undersuit]

Something more realistic then. Drive far enough behind the vehicle in front of you so that you can stop before falling down the same sinkhole/broken bridge/earthquake damaged overpass they just fell into.

[randomfinn]

Math seems to work out if you keep a 3 second distance to the car in front of you.

Google shows two-second rule when looking for "safe following distance" - I was taught 3 seconds and it seems more reasonable assuming slightly over a second reaction time.

[stevenwoo]

This has happened to me several times over 35 years of driving, driving along at freeway speed and the car in front of me swerves at the last second to avoid a stationary object either car or mattress or very recently dropped material from a truck in the road. Usually there is a clue because you can most of the time you can see how other cars other than the one right in front of you is reacting unless the car ahead of you is much taller or has super dark tinted windows. I wonder how accurate LIDAR is through the rear window and front windshield of the car ahead of you.

[mnw21cam]

I cannot vote this comment up enough. There needs to be a clear view of the obstruction in order for a person or an autopilot to see it in time. This is why you get a huge long string of cones easing people out of a lane before a road work obstruction. Similarly, warning signs should be placed before a stopped vehicle obstruction - there are quite a few countries in the world where not carrying warning signs for this purpose all the time is illegal.

[frgtpsswrdlame]

>Apparently the driver of the Tesla didn't have time to react to the firetruck as their field of view was obscured by a large pick-up truck that changed lanes seconds beforehand.

That changes the story a lot, do you know where you got that information?

[xya3453]

https://as.reddit.com/r/teslamotors/comments/7s9b9p/tesla_al...

[Someone1234]

So unverified, and if verified the auto-pilot system was following dangerously closely?

[jws]

Suggested highway following distance is two seconds. This gives you time to react to a decelerating vehicle. It is not sufficient time to stop if a stationary object appears, either because the vehicle in front dodges out of lane, drives over it with higher clearance than you have, or plows into it.

It is entirely possible for the vehicle ahead to have an escape path to another lane but you to be pinned in your lane.

Our traffic laws don’t provide for a zero accident environment. They just reduce the damage and suffering to a level society will tolerate.

[kbutler]

> Suggested highway following distance is two seconds.

Suggested by tailgaters?

1) A two-second rule is insufficient.

2) You need more time if you can't see around or through the vehicle ahead of you (and various other reasons, like weather, road conditions, being followed by a tailgater, etc.)

California driver handbook: """ Most rear end collisions are caused by tailgating. To avoid tailgating, use the “3 second rule”: ...

You should allow for 4 or more seconds or when:...

Following large vehicles that block your view ahead. The extra space allows you to see around the vehicle. """

[jws]

Most US States say two seconds. Some say three. German law requires 0.9 seconds, but studies show 41% of drivers there follow closer in relaxed conditions!†

Out here in the relaxed midwest most drivers in 60mph traffic seem to follow about 1.5 seconds.

It looks like highway planners expect to get 1900 vehicles per lane per hour at saturation, that averages 1.9 seconds between cars.

␄

† https://en.wikipedia.org/wiki/Two-second_rule (wherein it proclaims sleep impaired drivers in bad conditions should leave 6 seconds). If you think you need a six second reaction time, pull over and get out of the car.

[barrkel]

At 80mph, 2 seconds is about 240 feet (72 metres); 3 seconds 360 feet (108 metres). I'd expect to have my safety buffer merged into with a three second gap. It can still happen with a 2 second gap, but it's a lot less likely.

[tbirrell]

I was in a crash some time ago where the car in front of me jumped out of the way because the guy in front of him was at a dead stop. A "safe distance" for following a car that will have to decelerate to stop moving is a lot different if you are approaching a stationary object. It's not fair to expect either a human or computer to meet the latter standard on a highway were you expect everything to be moving at a speed close to the speed limit. There is a reason you can get a ticket for driving too slow.

[sjg007]

Why can't it detect a static object on the same path? I thought Subaru has a system that can do that.. At least according to the commercials it detects when a car in front of the car in front of you has stopped or slowed.

[deelowe]

> the car in front of you has stopped or slowed.

This is different from what happened in the tesla case. What happened here is that the vehicle in front of the car was moving and in view of the tesla's radar sensor obstructing the view of the firetruck. That car then moved and now a stationary object was suddenly in front of the car. From the Tesl's view point, an object just magically appeared somewhere in front of the car.

I'm not familiar with radar systems, but I imagine in this scenario the system isn't precise enough to know that this stationary object that suddenly appeared isn't an overhead sign or some other similar object that pops into the field of view of the radar system. It probably has something to do with radar not being extremely directional, constantly having stationary things pop up due to reflections and various objects in the periphery, having a limited sampling rate, and needing to do a filtering or other sorts of magic to make sure there aren't constant false alarms etc. I can see how cruising along at 50mph, the system doesn't have enough time to figure all this out and stop (e.g. not enough samples or there being a noise floor on stationary object data). It appears the correct way to solve this is with 3d lidar systems combined with sort of of mapping technology, but those are still too expensive/difficult to put into every day vehicles.

[sjg007]

I said "the car in front of the car in front of you". That car is not visible either since the car in front of you is blocking it. Subaru has commercials indicating this scenario is addressed as far as I can tell.

[undersuit]

It does detect static objects on the same path, but >99% of the environment is static objects. From the article:

>Radar knows the speed of any object it sees, and is also simple, cheap, robust, and easy to build into a front bumper. But it also detects lots of things a car rolling down the highway needn't worry about, like overhead highway signs, loose hubcaps, or speed limit signs. So engineers make a choice, telling the car to ignore these things and keep its eyes on the other cars on the road: They program the system to focus on the stuff that's moving.

[sliken]

Yes, subaru eyesight can detect stationary objects and apply the brakes. However they say that a full stop is likely (but not guaranteed) up to about 30 mph. They aren't clear on exactly what the likely result is at 65mph, but some braking to help mitigate the collision seems likely. Which is exactly what happened with the Tesla.

[Someone1234]

The Subaru system absolutely does handle this case. It uses visual cameras which watch the road ahead (just like your eyes) so they see what you see and react to objects/obstructions like you'd expect.

I'd had my Subaru slow due to a vehicle bumper sitting in the lane (from a crash that happened shortly before).

[kwhitefoot]

I have a 2015 Tesla S 70D with first generation autopilot (traffic aware cruise control and autosteering). The car does keep enough distance if you set it that way. The cruise control has a setting for the distance between you and the vehicle in front, the maximum distance is actually about three seconds separation. If you have it on that setting you have time to react, assuming you are paying attention in the first place. Might not be enough time to completely avoid an accident but enough to mitigate it.

[spyder]

That's interesting because in some cases the radar can detect if the second car in front of you breaks but the one directly front of you doesn't:

https://www.youtube.com/watch?v=FadR7ETT_1k

I guess this was in ideal conditions or maybe the Tesla in the firetruck accident doesn't have this software update.

[IshKebab]

That is nothing to do with any of this. There are two issues:

1. Autopilot didn't leave a big enough gap in front of the Tesla. Presumably because the radar has limited range, or maybe it was a big enough gap but the guy just wasn't paying enough attention.

2. Autopilot ignores stationary objects. This is a deliberate decision - apparently if you don't ignore stationary objects there are too many false positives from stationary objects you aren't driving into (signs, bridges, etc).

The root cause of 2. is that the radar doesn't have good enough angular resolution to say whether something is in your path or not - it can just detect things vaguely in front of you. The solution is probably LIDAR (which everyone except Tesla uses) or maybe some camera-radar data fusion, but obviously it doesn't do that at the moment.

[05]

The actual root cause of #2 is that, along with LiDAR, maps are also on Elon Musk’s “won’t do” list, so instead of comparing radar output to ground truth and detecting a stationary obstacle (which Waymo can do easily), Tesla tries to get by without any information about the world, and fails, badly and with sometimes fatal consequences.

[phkahler]

There is no such thing as "ground truth". Maps are for navigation, not safety. IMHO the fact that companies keep using radar and lidar indicates that their vision systems are not as good as they should be.

[surrealize]

So you have maps that record the location of stationary signs etc. and then have the car stop if it gets a radar return from a stationary object (e.g. fire truck) that's not on your map? Then when someone puts up a new sign you're slamming on the brakes until the map gets updated.

Not being able to tell if a stationary object is something you're going to hit or not (like LiDAR or stereo cameras might do) is more relevant to this case than maps.

[ortusdux]

The issue at hand is that the software filters out stationary objects. The case you describe only happens if the tesla is tracking the two cars in front of it and the further one breaks.

[rfugger]

That suggests the fire truck was stopped in a bad place and had not set up enough warning signs up the road that there was an obstruction in the road. I wouldn't be surprised if the fire truck was found responsible in this case. (That's not to say that auto-driving systems shouldn't be improved to better handle this situation by at least braking before impact!)

[cr0sh]

I had something like this happen to me about a year ago (October 2016); funny thing was, at the time I was enrolled in the Udacity Self-Driving Car Engineer Nanodegree. After the accident (which was completely my fault), I wondered how a self-driving car could have handled it.

Basically, I rear ended somebody - but the details of why that happened are interesting to me.

I was going down a road I usually travelled to go to work that morning; two lanes each direction with a middle "suicide" lane.

Traffic was fairly heavy, as it always is in the area during morning traffic; there's a school not too far ahead in the direction I was travelling, and traffic "bunches up" and slows in the area, thanks to a crosswalk, people dropping kids off, and a "radar speed limit sign" that tells drivers how fast they are going in relation to the speed limit when school is in session (causes people to hit their brakes). Furthermore, not too far after the school is a stoplight for an intersection with another similar road.

Where I was at just before the accident was crossing a neighborhood street at a controlled intersection; also at that intersection, the suicide lane changes to an unprotected left turn lane.

So there I am, tooling along at my normal 40-45 mph (appropriate speed for the street I was on). Coming up on the intersection, a tractor-trailer semi was in front of me; the driver decided to make a left hand turn at the intersection, and got into the suicide-turning-into-a-left-turn lane. I decided to accelerate a bit to go around him. Now - I was kinda in an "autopilot" mode, not paying as much attention as I should have.

The traffic in front of me - thanks to the conditions I mentioned - which were typical of the morning time period, should have clued me in to "slow down" (which I have since taken to heart). That area, due to the traffic and conditions - is a "stop and go" situational nightmare. Traffic moves a bit, slows, maybe stops, starts again - and people do the typical: They don't keep their foot on the brake, so while they are "going slow" or even "stopped" (idling, not enough power to move) - their brake lights aren't "on".

So there I am - going around the truck - and "traffic ahead of me" registers, but I didn't see any brake lights, so while in my "autopilot" morning haste/haze/whathaveyou, I made the incorrect assumption that traffic ahead of me was moving; accelerating, maybe not going as fast as I was, but getting there. Which was the wrong assumption, of course.

The next thing I knew, I recall that the car in my lane ahead of me didn't have his brakes applied enough to turn his brake lights on, but wasn't moving anywhere near my speed; then he hit his brakes full (causing his lights to go on), and I slammed on my brakes just a bit too late in my realization. My speed dropped instantly, but not quick enough - I was probably going 15 mph or so when I rear ended him.

I was driving my 1996 C1500 pickup, his was a small crossover-like vehicle. Not much damage on my end; his bumper was mashed, lights broken, etc. We pulled over, exchanged insurance info, no cops involved, and went on our way. I called my insurance immediately, of course, and let them know what happened.

So it was a combo of things; my "autopilot" inattention, my speed, the traffic situation, the way people were "braking", going around a semi truck that was blocking my view then "road clear" ahead - it all came together in a "perfect storm", ending up with me rear-ending someone.

I tend to think that an autonomous car, or one with automatic braking (features not to be found on my truck at the time), would have been paying "more attention" and would have seen the car ahead of me not moving as fast (never mind the lack of brake lights), and would have hit the brakes and came to a stop much sooner. Indeed, had I been paying better attention, and going a bit slower (perhaps only going 30 or 35 mph), I could have applied my brakes much sooner, and avoided the accident.

Lesson learned, I guess.