Any comments or analysis about the NHTSA’s 10-month study and recent report on Toyota?

[James' Reply: Yeah I should write a follow-up.]

Because when something like this happens (http://www.straitstimes.com/BreakingNews/Money/Story/STIStory_503200.html – this is about a Norvegian who saw his Prius accelerate), they will look like fools (if not like liers ).

What is curious is that the Norvegian Toyota say exactly the opposite as US Toyota, they say that the driver story “The (driver’s) description strengthens our conviction that our client was in a situation where his vehicle accelerated in an uncontrollable manner”.
Now, I wonder what will US Toyota say about this .

I searched for more information on this, but I could not find the whole Toyota statement.

I have no idea if this is what the Prius is designed to do...this is what our 2008 Prius did while moving straight ahead under relatively low-speed, cool-weather, dry-road, low-humidity conditions with a cellphone present and ON but not activated in the vehicle; with the radio off, the lights off, turn signals off, emergency flashers off, wipers off, heating system on LOW, windshield heater ON, doors and windows closed, no passengers in the car, one third of a tank of fuel on board, and the “Maint Req’d” light illuminated probably because it was programmed to come on the instant the mileage hit some magic number for warrantee service and not because maintenance is in fact required.
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I was struck by the fact that [He said dispatchers tried to talk him through ways to stop the car, but nothing helped.] so can I assume that they didn’t suggest to try the break pedal and the emergency break at the same time? I’d love to hear that call…

David

interesting. Wonder if the lawyer will be calling you.

This is the age-old question again. What do you do with non repeatable defects? I’d say in this case investigate but be aware there might be no answer. Wait for more cases. That migt sound cruel but:

a) Compared to accident stats for the Prius this is not even a blip so relevance can be questioned
b) just imagine they introduce a fix. And that they fixed the wrong thing (they can’t test it because it is not repeatable). Isn’t then the danger of damage even higher? Should not be erred on the side of less risk? Like the aviation guys do?

There is a whole world of uncomfortable business and risk decisions here that are not really customer compatible but reality nonetheless. I have the distinct feeling someone is trying to get Toyota. They are finally vulnerable and the media is exploiting that out of proportion. So go figure.

Anyway I still liked your disection. Really good example of staying objective.

Thanks
Oliver

[James' Reply: One of my posts from long ago, here is all about reproducing intermittent bugs.

This has become such a large PR problem for them that I'm sure they want to find and fix the problem just on general principles.]

In the AP article it stated “In Sikes’ case, Toyota said it found he rapidly pressed the gas and brakes back and forth 250 times, the maximum amount of data that the car’s self-diagnostic system can collect.” So the log maxed out at 250. Could it have been hundreds or thousands more instances of alternating pedal presses? This sounds like a potential infinite loop problem. Perhaps Mr. Sykes sequence of gas/brake “clicks” put him in a loop.

If I was a tester assigned to investigating this bug report I would want to know:

Were these the only items in the log file? Were they at regular or irregular intervals and how long between events i.e. do the events look more like a computer produced them or human?

Additionally, is there different logic for braking depending on speed and force of the pedal press? I would guess there is. Perhaps there is a bug only at certain speeds at boundary conditions.

It will be interesting to follow this story in the coming weeks

I have one point to question, though. You say:

I don’t know much about the design of a Prius, except that my understanding is that there are no physical cable linkages. It’s software driven. When you press the brakes you are essentially double clicking on the “brake” icon with your foot mouse, hoping that the operating system agrees to apply the real brakes. A Prius is basically a video game console connected to a car. You drive the console, not the car.

and:

Eventually, a California Highway Patrol officer was able to catch up to Sikes and used the patrol car’s public address system to instruct Sikes to apply the brakes and the emergency brake at the same time. That tactic worked, and he was able to stop the car.

I’d like to know if Sikes had tried the emergency brake alone, before this. Had he tried both at once before this.

I can understand if he did not try both at once, because a normal driver would think if they don’t work individually, why would they suddenly work together? But in a drive-by-wire system, everything is mediated by software, and software can get into strange states. It’s technically plausible that only with both brake controls activated the software could be bounced out of whatever strange trance it got into.

However, I’m not sure that’s entirely true. While the regular brakes may certainly be (and probably are) controlled by software, so as not to harm the engine, it’s my understanding that the emergency brake of a Prius works just like the emergency brake of any other car; that is, it’s a physical mechanism.

Having driven a Prius several times myself, though I haven’t examined it in detail, I’ve experienced the ratcheting/clicking sound and haptic feedback when engaging parking brake that all parking brakes have, and when releasing it, it still feels like a physical mechanism. I’m not inclined to think that the emergency brake is applied through software and remains applied when the car is completely turned off. I’d also be surprised if there were no single, purely physical fallback braking mechanism and the Prius instead relied solely on software for its braking; that sounds like an accident waiting to happen (even more so than latent and elusive software bugs).

So this leads me to question not (only) the order in which these things were tried, but the accuracy of the statement that applying both of the braking mechanisms at the same time was the actual solution. Thoughts?

[James' Reply: I want to know more about this. I Googled a bit and didn't find the specs right offhand. My Dad has a Prius, so I'll ask him.]