Lost in the news coverage of the Toyota acceleration debacle is the value of a good programmer. Consider that Nissan and the German car makers (perhaps because they use components from Bosch?) all have a line of a code that says “IF the brake is pressed THEN ignore accelerator input and set throttle to idle”. It wasn’t a top executive who put that line of code in, but a humble computer programmer. The Toyota programmers didn’t do this and now their company is losing perhaps billions of dollars in long-term sales and profits (the value of the company in the stock market has dropped by approximately $20 billion).
In http://www.nytimes.com/2010/02/18/business/global/18toyota.html, the Toyota top executive is reduced to characterizing the already proven-to-fail system as “fail-safe”:
“Toyota uses many sensors to ensure its electronic throttle systems are fail-safe,” Mr. Toyoda said. The company has conducted “rigorous tests” of the system to make sure it did not trigger sudden acceleration, he said.
Is it possible that we’ll see more respect given to programmers when the dust settles from this?
[Separately, I experimented with my 2007 Nissan sedan, touching the brakes while flooring the accelerator. This is the one time in three years that I have looked at the huge tachometer hogging dashboard real estate! It slowly rolled from 2500 RPM to 1200 or so.]
Probably less respect. Programmers are in the unenviable position that their best work is invisible. The general population is so used to the idea that computers can be used to do “magic” that failures become notable and successes become expected.
As long as “pressed” means “pressed more than 80% of its throw”, it sounds like good logic to me.
“Brake pressed at all = stop throttle” has no place in any sports car at least.
I’ll bet it’s not a software problem but a marketing problem.
It’s surprising (to me, anyway) how many “two-foot” drivers there are. Drive-by-wire systems where the throttle returns to idle when someone “rests” their foot on the brake drive these folks nuts.
But even the Mercedes/Bosch systems have their bugs. My Sprinter RV would occasionally go into “fail-safe” mode and reduce power to where it wouldn’t go over 35mph. It does this when it detects a fault in some drivetrain control sensor. But every time it did this you just had to pull over, turn off the key for 30-seconds or so to reset the computer, and it would be fine until it happened again a month or two later. No fault stored in the computer so the dealer was no help.
Even Honda has their issues. My Honda Element with stability control had a problem with one particular on-ramp in Portland. This ramp has an expansion joint on a curve and it confuses the Honda stability system. Nothing like going up this on-ramp in heavy traffic and the car suddenly deciding on its own the correct thing to do is jam on the brakes.
I sometimes touch the brake while on the gas at the same time as a means of trying to shake a tailgater. The brake lights coming on usually gets them to back off. Seems like I wouldn’t want to do this in a car that has this one line of code in it!
Jim: The throttle roll-back is fairly gradual, so I think that you could do what you are currently doing in a BMW, Mercedes, Porsche, VW, or Nissan.
Jeff: As far as “no place in any sports car” goes, BMW and Porsche sell themselves as sports cars, don’t they? I haven’t heard of anyone complaining about a lack of sportiness because of this feature (maybe because they spend all of their time stuck in traffic and seldom get to drive more than 45 mph in their 200 mph car).
Maybe I am old fashioned, since I drive a 20 year old Peugeot with almost no computers inside, but these kinds of features make me wary. At least, I’d like to be able to turn them off if I want to. When I drove my father’s new Pontiac Vibe (GM/Toyota joint venture) for the first time, the stability control system engaged while I went around a fairly tight corner on Soldier’s Field Road. It took me a few moments to figure out what was happening, but until then I was really startled to be pressing the accelerator and yet the car was slowing down.
What I like about the Peugeot is the directness of the controls. Even seeing the digital clock dim each time the turn signals blink due to the corresponding drop in voltage is charming. I realize the Vibe is not a sports car, but I do find it a little depressing that my 20 year old sedan can take that corner at full speed, while a brand new sporty XUV apparently thinks it was about to roll over. Although the Vibe is no fun to drive, it has a built-in 110V inverter, one of the better electronics additions I’ve seen in a new car in a long time. It also has a super-advanced ICE that is extraordinarily efficient due to cleverness in starting and stoping individual cylinders rapidly.
As far as I can tell, the major innovation in automobiles in the last twenty years has been introducing computers inside cars in all sorts of places where they weren’re before, and yet keeping reliability essentially constant.
I suspect that if the clutch is on the floor that the sports cars with electronic throttles allow for the brake and gas to also be pressed simultaneously (i.e. for so-called heel-toe driving/downshifting). This is less useful in the automatics.
I believe Jeff is referring to the art of heel-toe driving
http://en.wikipedia.org/wiki/Heel-and-toe
blipping the throttle helps mesh clutch/drive train speeds to minimize wear and tear during a race. Many newer sports cars “blip” automatically such as the BMW M3 SMG transmission but there are many others capable as well such as certain Ferrari’s. Watch any James Bond movie and listen for the “blip” as the stunt driver expertly revs the engine while downshifting the Aston Martin into a power slide :>
Umm, I know we’re all agile now, but this isn’t the sort of thing that should be up to a programmer. Accelerator and brake pedals are very simple inputs; there should be a very simple state machine in the spec that describes EXACTLY what effects they have.
Not enough to just test for the clutch depressed–what if you’re doing a heel+toe double clutch downshift? Then you’d have brake pressed, blipping the throttle, the clutch out, and the transmission in neutral.
I’d hope the programmers would trust manual transmission drivers to do the right thing and not override the driver inputs. After all, with a stick you just put the clutch in or go to neutral–no run away. (Although I guess if you’re paranoid then you can start to worry about hydraulic or clutch cable failure along with stuck throttle, but that’s two major simultaneous failures.)
I would never buy a vehicle that does not allow me to break while modulating the gas pedal. This is a fundamental safety issue for me to be able to do so: weight transfer in the turns, controlled skids etc. The other question is that not many people care about various driving technics and safety.
Couldn’t that line of code fail in the opposite way of what is expected? For example, if I pull out into an intersection from a secondary road and get a false braking signal, that would cause me to fail to accelerate and get smashed.
I often find that this is how software testers introduce bugs into applications. They find a rare edge case of failure which requires a solution which increases complexity and other problems, because the fix was not as well thought out as the original design.
Matt: Probably it could, though as I noted, the rollback is pretty gradual. I guess for maximum safety we need a car that runs at full power all the time (so you are guaranteed to have acceleration) and then 2″-thick brake discs, each of which is the same diameter as the tires and fan-cooled. We will simplify the control system by having only one pedal and it will control the amount of braking from our monster fan-cooled brakes. As brakes can also be referred to as “retarders” we can call our new car “Full Retard” or perhaps “Maximum Retard”.
Philip, NYTimes is reporting today that this very idea is probably going to be mandated and Toyota is already moving to put it in their new vehicles.
http://www.nytimes.com/2010/03/03/business/global/03toyota.html?hp