> If I'm paying attention and I prevent Autopilot from getting me into an accident, why have it on in the first place?

Because it takes less mental effort to watch for the exception case rather than constantly adjusting speed/heading/etc.

Also something that's rarely mentioned is that in it's current form AP's killer-feature is rush hour traffic. In those situations you're dealing with <20 MPH and tends to be the most mentally taxing.

In my small sample set(~30k AP miles) I've found the mental load for driving long distances and rush hour traffic to be significantly less.

How do you know you watched for the exception well enough to react fast enough to prevent disaster when it happened?

At ~30k miles, chances are you haven't seen enough exceptions to make a judgment on that.

It is hard to stay focused on jobs that are extremely dull, except for the rare cases where they aren't.

There's tons of research on this because there are many people in that situation (watching radar screens for incoming ICBM's, guarding a facility, luggage screening at an airport, etc)

Oh, I saw plenty of stuff in those miles where I had to react.

Flying tires, wildlife jumping out. Heck, just yesterday had someone merge into the lane with no signal. Just because I'm not providing steering inputs doesn't mean that I'm not constantly scanning traffic.

This makes intuitive sense but is not borne out by research such as [1]. The < 20 mph scenario, one of traffic, consists mostly of stress and the general unpredictability and frustration of the whole scenario.

The problem of Level 3 autonomy is not cognitive load but the general lack of active feedback on the one hand, and a lack surprising events to mediate the allocation of attention on the other. It makes sense, the longer you're encountering non-events, the more difficult it will be to justify alertness. Surprise guides attention which in turn is strongly correlated with alertness. The longer one must remain alert, especially without surprise, feedback or reward, the higher the levels of subjective effort and mental fatigue.

Intuitively, if you imagine that only a few things are filtered to attention, the less surprises, the more predictability, the more difficult it is to select what to attend to, the more likely your mind will begin to wander. This is one explanation for the finding in [1]:

   The fact that the number of false alarms increased suggests 
   that the rather dramatic increase in missed targets was not 
   due to a simple reduction in the number of responses: 
   the number of responses to nontargets even increased. 
   This suggests that the observed deterioration of performance 
   is not caused by task disengagement but may result from increasing 
   difficulties for subjects to correctly identify targets

This is also related to the very complicated aspect of maintaining concentration over extended periods of time (you can play a complex but engaging game for longer than you can a dull monotonous task) and the explanatory failure of a resource depletion account. There is as yet no completely satisfactory account for why perceived fatigue occurs but all the best models have attention, motivation and reward in common.

[1] In the linked article they specifically call out driving as an activity sensitive to mental fatigue http://www.sciencedirect.com/science/article/pii/S0926641005...

> Because it takes less mental effort to watch for the exception case rather than constantly adjusting speed/heading/etc.

Yes, this!

The argument that drivers are safer if they are forced to pay attention all the time is ridiculous, you can use that to argue against every feature on the car! Servo steering is bad, you don't feel the road properly! Automatic gearboxes are bad, you're not in tune with the engine! ABS brakes are bad, you should know how to brake so as not to lock the wheels! Traction control is bad, you should never drive on surfaces where you're not in 100% control of the car! Blind spot radars are bad, you should always look around you and make lane changes responsibly! Bla bla bla.

The current Level 2 autonomous systems makes it easier to do the right thing when driving. Used correctly, they lessen the cognitive load, but you have to learn how they work, what they can and cannot do, just like you need to know what situations your traction control systems or anti-lock brakes can save you from. They're not magic, they're just one more helper system.

The difference is in human-enhancing features (ABS, traction control, gearboxes) vs. human-replacing features (collision avoidance, routing, situational awareness).

The best human drivers can get by without the first set of features.

That's a completely arbitrary distinction, you are essentially saying that stuff that was in cars when you learned to drive is all natural and perfectly fine, but stuff that got introduced afterwards is suspicious and bad and you don't like it.

How is routing not human-enhancing? It makes it easier for you to choose which route to take? How is an automatic gearbox not human-replacing, it eliminates the need for a human to shift with the shift stick?

Maybe a better phrasing would be "features that let you focus on the road more" (e.g automatic shifting, ABS) vs. "features that let you not need to focus on the road" (e.g. lane assist, automatic braking, radar cruise control)

> In my small sample set(~30k AP miles) I've found the mental load for driving long distances and rush hour traffic to be significantly less.

Interesting---how did you measure this?

Had about ~7k on the odo when we got the AP update, 37k now. Large majority of my miles are 300mi roundtrip weekly commute.

Oops, my question was ambiguous—I was actually wondering how you measured "mental load", as you put it.

Ah, misunderstood :).

I've been doing the same ~7hr drive + workday for 2 years. Both myself and my wife noticed I was a lot less wiped out after AP. We have the car ~3 months before AP so it was a pretty controlled change.

> If I'm paying attention and I prevent Autopilot from getting me into an accident, why have it on in the first place?

The same reason you have cruise control - it doesn't do everything for you, but it helps reduce cognitive load in some basic areas, which reduces fatigue over the long haul.

> The question is if fewer people will die on a per-mile adjusted basis.

Last I heard, Autopilot was MUCH safer per mile.

Not the numbers I've seen. Estimates range from about the same as humans, if you compare raw miles driven, to considerably less safe if you just compare against highway miles, which is where Autopilot is used. There's also the issue that, with only one fatality, the error in estimating the rate is quite high.

Will more people die than would have with AutoPilot?

If you quintuple the number of Tesla kilometres per year but only triple its safety, you will still have more injuries and fatalities.

For every Tesla that is now able to recognise a truck cutting across a highway and brakes in time to avoid a fatal collision you will have new bizarre scenarios like following behind a truck that dislodges overhead objects, which a human would have avoided but a Tesla's computer didn't see, leading to a human getting crushed by a bridge falling down.

I would also expect a short learning curve for Teslas to acknowledge the emergency stop water curtain signs.

But the short version is yes, SDC will result in more deaths even though they get relatively safer and safer.

https://youtu.be/NoTMC-uxJoo

Let me ask a different question. For every accident that happens with AutoPilot and a non AutoPilot car, would it have happened if every involved car had AutoPilot?