Designing Unsafe Cars


The LA Times has an interesting article about problems with Toyota and Lexus cars [1]. Basically there are problems where the cars have uncontrolled acceleration (there seems to be some dispute about whether it is due to engine management or the floor mat catching the accelerator pedal). When that happens the brakes don’t work (due to the vacuum power-assistance for brakes going away when the engine is at full power) and a terrible crash seems inevitable.

There are suggestions that the driver should shift the car to neutral and discussion about how the Toyota gear selection makes that difficult. Some years ago I was driving an automatic car on a freeway at 100Km/h and the engine stalled (due to a problem with the LPG system). I had become used to never touching the gear lever while driving so the possibility of moving the gear lever one notch to neutral didn’t occur to me. With a dead engine in gear the car slowed rapidly which is quite dangerous when surrounded by 100Km/h traffic. Fortunately I was able to swerve into the emergency lane (across one lane of active traffic) before the car slowed much. That was in a relatively controlled environment with a gear shift mechanism that is a lot simpler than that which is common in some of the more expensive cars.

According to Wikipedia the maximum speed limit in the US is 80M/h [2]. It seems to me that Toyota is being irresponsible by selling cars that can sustain 120M/h, while the probability of surviving a crash at 80M/h is quite low, it seems likely to be a lot greater than the probability of surviving a crash at 120M/h. Also if a car is out of control at 80M/h then the driver will have a lot more time to work out how to put the engine in neutral or turn it off – the lower speed will extend the time available by more than 50% because bends in the road can be better handled at 80M/h.

It seems to me that it would be a feature for the car owner to have the car limited to a speed that is not much greater than the speed limit. According to Wikipedia the highest speed limit in Australia is 130Km/h (in NT), but it’s 110Km/h in all places where I have driven. If my car had a governor to limit the speed to 115Km/h and a switch to change the limit to 135Km/h in case I ever drive to the NT then it would not affect my driving patterns (I rarely drive on roads with a 100Km/h limit and almost never drive on roads with a 110Km/h limit) – but it could reduce the probability of things going horribly wrong. Also one thing to note is that last time I checked car tyres sold in Australia were only required to operate safely at speeds below 190Km/h (118M/h), so a Lexus that went out of control at 120M/h in Australia might risk a tyre blow-out – which admittedly would only make things marginally worse.

A governor for the reverse gear would also be a good feature. Some time ago a granny got her foot stuck on the accelerator in a car park and caused serious damage to her car and a parked car – after passing close by where I was standing. I don’t think that there is a real need to do more than 5Km/h in reverse, limiting the speed would give pedestrians a better chance of escaping parking accidents.

One serious problem with some of the Toyota and Lexus vehicles is that it apparently takes 3 seconds to turn the engine off in an emergency! I’ve been driving for almost 20 years and experienced a number of dangerous situations, all of which were essentially resolved (for better or worse) in significantly less than 3 seconds. A 3 second delay is as good as a 1 hour delay for safety critical systems.

Also if the accelerator and brake pedals are pressed at the same time then the brake should take precedence. It seems quite obvious that whenever both pedals are pressed hard then the driver would probably prefer hard braking to hard acceleration.

If you look at industrial machinery (robots, lathes, etc) you will always see big red buttons (or whatever color is used for emergency stop in your region) that are clearly marked and obvious – to the workers and to bystanders. Escalators have less obvious red buttons but they can still be shut down in an emergency. It seems to me that there are potential benefits to having an emergency shutdown button in a car, maybe in a position that is accessible to the front-seat passenger in case the driver is incapacitated. Such a shutdown button wouldn’t do anything extreme such as fully activating the brakes (which would be very bad on a road that has high-speed traffic), but would prevent acceleration (with some sort of hardware control to avoid software problems) and maintain power to the brakes and the steering.

One thing that needs to be considered is that people tend not to do the most logical things when in an emergency situation. It needs to be possible to do whatever is necessary to save your life without any great deal of thought. Pushing a big red button is easy, holding down the “on” button for 3 seconds or even navigating a gear shift to an uncommon setting is a lot more difficult.

It seems to me that there is also an issue of driver training. If putting an automatic car into neutral and cruising to a stop was part of the test for new drivers then the results of such car problems might not always be so bad.

But I don’t expect there to be any serious changes to driver training or car design. People are too accepting of road deaths.

Don Marti has expressed a plan to never buy a vehicle with an automatic transmission because of this issue [3]. But the number of new vehicles being sold with a manual transmission is steadily reducing. An automatic transmission allows better performance (F1 cars have used them for ages), better fuel efficiency (you could never make a manual Prius), a more comfortable ride (the Hybrid Lexus keeps winning the Australian Luxury Car of the Year award), and allows less skillful drivers. Unless Don wants to ride a moped or drive an old car then I expect that he will be forced to get an automatic transmission. Then of course he will still be at risk of other people having car problems (the LA Times article mentions a third party being killed after an out of control car hit them).

Also I expect that the extra safety features that are implemented in luxury vehicles such as the Lexus would save a few lives, they should save enough to outweigh the number that are lost on the rare occasions when the car goes out of control. Other luxury cars such as the Mercedes S class have great safety features and don’t have a history of going wrong in a newsworthy way. A second-hand S Class Mercedes was surprisingly cheap in the UK last time I checked, cheap enough to make it worth considering the importation of one to Australia.

But my solution to these problems is to try and minimise my driving. A 1.5 ton Lexus driving out of control at the maximum speed possible in urban streets won’t do much damage to a 20 ton tram.


23 thoughts on “Designing Unsafe Cars”

  1. Joey Hess says:

    As recently as 10 years ago, there were parts of the US with no hard speed limit. Could happen again. It’s also possible to drive from the US to other countries with other laws. Having hardware that enforces one country’s laws while in another country is an interesting area..

  2. btmorex says:

    Automatic transmissions are *not* more fuel efficient for most cars at least. Actually, I’m not really sure where you got that idea; are you only talking about hybrids?

    Also, manual transmissions are generally cheaper and lighter as well (you can argue whether lighter is better, but at least it makes the roads a little more safe for everyone else).

  3. btmorex says:

    Too bad I can’t edit, I actually disagree with most of your assessment of auto vs. manual transmission.

    In addition to what I wrote above, calling f1 transmission automatic is really stretching it. The driver still controls when gears are changed. The main difference is that the clutch is electronically controlled with allows for much faster shift times. It’s really not comparable to typical automatic transmissions that you find in reasonably priced cars.

    I also disagree with your assessment that auto transmissions offer smoother rides. Take for example the common case of passing someone on a multilane road. You need to downshift to accelerate, but the only way to actually get an automatic transmission to downshift at those speeds is to floor it. That’s much less smooth than simply downshifting and accelerating at a reasonable pace with a manual transmission.

  4. The main problem is not any of those you mentioned, but the (almost always forgotten) fact that automatismes steal power from the user.

    A traditional car, with all its three pedals, would not suffer those failures. The driver can always disengage the wheels from the engine just by pressing the pedal, keeping his hands where they’re needed. He can also fully press brake pedal if he wants, because it is a different foot. And he will not unadvertently press brake and accelerator pedals at once! (and he can do it, if he wants to).

    Manual cars are by far preferable, since they keep (like Free Software) the decision power in the user, where it belongs to. Thus, things like thinking that automatic cars are better because they (I cite) allows less skillful drivers is like thinking that Windows is better for the same reason. The problem is not the car or computer being “complicated”, but the user being not skillful. If you don’t know how to make a surgery, you don’t do it. If you don’t know how to drive, don’t drive. And if you don’t know how to use a computer, don’t expect anybody fix your disasters, trojans and viruses.

  5. Adam Sloboda says:

    Maybe Don wants to import car from Latin America or Europe where manual transmission prevails.

  6. John Slee says:

    As another reader commented — F1 cars don’t have automatic transmissions.

    The difference between an automatic transmission and a manual (including dual-clutch as is popular now) transmission is that the torque converter (auto) or flywheel+clutch (manual). F1 transmissions are manual transmissions with fancy electronic control. For a while (ending 2006, perhaps?) they had fully automated downshift through multiple gears, which was pretty amazing to hear in action.

    I agree with you on the instant kill switch idea, I think. As a motorcyclist the use of such switches is second nature. Motorcycles are designed so that you can hit the switch without thinking or looking, without taking your hand off the throttle grip, using just your right thumb.

    On the speed governer stuff — Nissan have a system in their current-model GT-R that uses a GPS to sense when it is on a known racetrack and removes some artificial limitations. This approach would be rather better, I think, than a driver-controlled 115/135 km/h switch. It’s not as if the Barkly Highway is in a tunnel. I do disagree with the governer approach entirely, but that’s for another post

  7. etbe says:

    Joey: It seems unlikely to me that you would want to drive an expensive Lexus to a part of South America with no speed limits. There seems to be a strong correlation between lack of laws about safety issues (such as speed limits) and a government that lacks the money to build the quality of roads that suit a luxury car. Also even if you wanted to drive a Lexus in such an area you probably wouldn’t want to do it at 120M/h. But that said, a well designed governor could be adjusted by a mechanic without too much effort.

    btmorex: A simple automatic transmission is not more fuel efficient. But an automatic transmission does allow the use of technology that increases fuel efficiency. The Prius uses several technologies that simply can’t be implemented with a manual transmission (CVT and full-hybrid operation for starters). I agree that a lighter vehicle is generally a good thing (more fuel efficient for starters), but I doubt that the difference in the mass of the transmission makes much of an impact. Those 4WD vehicles with manual transmissions are a lot heavier than the typical car with an automatic transmission!

    All the recent automatic transmissions have a lever for tiptronic control so the driver can force a gear change if they wish. I believe that the F1 cars use electronic controls which mean that there is no physical override when things go wrong. But compared to all the other risks of F1 driving it’s really no big deal.

    Noel: If the accelerator pedal in a manual car is stuck down by a floor mat or a mechanical failure then pressing the brake will be less effective. The LA Times describes how the vacuum used for power assisted brakes goes away under hard acceleration.

    I don’t think that the risk of pressing the brake and accelerator at the same time is much different for automatic and manual vehicles. The only difference in that regard is the issue of drivers who use their left foot for the brake when driving an automatic car. That might give them a better reaction time when braking but also wears out the brakes.

    When using free software I like to have the boring stuff done for me. I insert a Fedora or Debian CD into a computer, tell it basically what to do, and then a few minutes later I have a fully configured workstation that offers the users a choice of GNOME and KDE. This is so much better than things were in the early 90’s! Let’s face it, the majority of drivers are not particularly skillful. I think it’s best that they use their meager car skills for concentrating on not crashing rather than using the clutch correctly.

    As for saying “if you don’t know how to do X then don’t do it”, that doesn’t work. For Australia and the US almost everyone has to have a car. The cities are designed for driving. Australia is a lot better than the US for public transport, but your life will still be limited if you don’t drive. This is unlike most of the Netherlands and much of the EU where cars are impractical and you can do everything you want without one.

    I think it’s entirely reasonable for someone to expect someone else to set up their computer – and pay them accordingly. I couldn’t repair my car either.

    Adam: I think that the manual transmission will go away in those countries too.

  8. etbe says:

    John: Detecting when on a race track is overly complex, it requires software and therefore is subject to a software failure. Also new race tracks can be built at any time.

    One thing I have not advocated in this post is legally enforcing the use of governors for road vehicles, as you say that is for another post.

    If a car buyer is happy to have their car limited to slightly more than the maximum speed in their country (or any other speed for that matter) then there is really no argument against it. I believe that Lexus could use such a feature to help salvage their reputation, insurance companies would probably offer discount rates for such vehicles, and everyone who ever lends their car to their 18yo son would just love such a feature!

  9. Adam Sloboda says:

    According to wikipedia sources: As of 2008, 75.2% of vehicles made in Western Europe were equipped with manual transmission, versus 16.1% with automatic and 8.7% with other.

    So there is majority of new cars made with manual transmission in addition to even larger majority of used cars. Automatic transmission is usually option only for luxury class.

    They will go away but very slowly. Still it may be replaced by Dual Clutch and not entirely automatic.

  10. I guess it could have changed, but the last time I was in Montana it had virtually no speed limit during daylight hours. It did have posted speed limits, but the fine was $5US on the spot.

  11. etbe: I’m not saying that we must not use what technology gives us, but that we have to educate people to use it. “Making things easy” like Windows or automatic cars do is not the same than “Making things easy” like debian-installer does. The problem is that automatic things make people to forget how to think.

    You say that “As for saying “if you don’t know how to do X then don’t do it”, that doesn’t work. For Australia and the US almost everyone has to have a car. The cities are designed for driving.”

    Well, you yourself are pointing the problem: people has been moved to think that they need a car. And things have been set up so that they feel forced to that, improving streets and road rather than public transport. At least in Spain you need to have an exam to obtain the driver license. You need to know how to use the three pedals. So people can use cars, because they know how. It has been the cause of unnumerable headaches to IT people the users of computers who think that they can manage them.

    About your first point, in a manual car if the accelerator pedal stucks down you still can use the disengage pedal to avoid transmitting more power to the wheels, and the brake pedal to stop the car at the appropiate rate. In fact, you’re teached to do that. In an automatic car you simply can’t. And it is true that the servomechanism will not be as effective as normally, but in the manual car there will be no engine accelerating the wheels.

    Oh, and no. The risk of pressing both accelerator and brake pedals at the same time is very different if you have one foot for each one than if you have one foot for both, and the left one is quite far away in the disengage pedal (and your muscular memory tells it not to move right to the brake one).

    If you can not repair you car, go to a professional to repair it. Sounds normal, didn’t it? If you dont know how to set up your computer, go to a professional – and pay him. Yes, of course. By the same rule, if you don’t know how to drive properly a mortal and weigthly machine, use a taxi, bus or metro. And if there are bad service, that’s what needs to be changed, not the “difficulty” to use an inherently complicated machine.

  12. sam says:

    My motorcycle has a kill switch. I hit it on accident once on the freeway going 90mph in the left lane. I very quickly lost speed, caused a massive back up of traffic, there was no left shoulder on the road just a concrete barricade as there was construction on the median, had to slowly coast across all four lanes of traffic, nearly getting killed, only to find out I had hit the kill switch…Clearly this isn’t the answer… People simply need more training. The more junk you put on a car just reduces its over all reliability and cost of maintenance (I used to work at a family owned auto shop). Besides, people already have enough trouble just dealing with the 3 main things in a car (steering wheel, gas, brake)

  13. Charles says:

    Does the Toyota foot break cut out under hard acceleration as an aid to hill starts, and as a way of easily controlling idle-creep?

    When comparing automatic and manual transmissions, the degree of automation and intelligence of the system allows for huge scope in efficiency and power transfer characteristics. Ask Wikipedia about CVT transmissions and torque converters.

    A Formula One style transmission is mechanically similar to a road car manual transmission, with a friction plate clutch and dog-locked sequential gearboxes with helical gears. Seamless shift gets a little more complicated but the physical resemblance is there, the big difference is in the electronically switched hydraulic actuators rather than traditional clutch pedal and stick shift.

  14. furicle says:

    There’s lots of half truth and misinformation in that article.

    1 – Vacuum brake boosters retain vacuum for several pumps of the pedal, they don’t just quit working.

    2 – It’s not that hard to stop a car without any boost at all – especially if you are panicked. It’s the darned Audi thing all over again where people swear they had their foot on the brake, but guess where the camera proved it was? Firmly on the gas. Points to badly designed pedals perhaps.

    3 – Automatic transmission shift gates are designed to let you just ‘whack’ the shifter and it will end up in neutral. Try it on your own car now if you never have. You should know how it works. While it’s possible the dual track semi-auto style in a Lexus might be a bit confusing, I just can’t believe it doesn’t still work that way there.

  15. Peter Moulder says:

    If anyone is considering [advocating] implementing the decision to limit speed (whether forward or backward) to reduce accidents, then please remember to balance against the times when the extra speed is needed to avoid an accident. Especially in the case of reversing, where we’re trading 5–20km/h collisions against avoiding potentially much higher-speed collisions from other vehicles.

  16. etbe says:

    sam: A poorly implemented kill switch doesn’t necessarily prove that a kill switch is always bad. Also motorbike leathers are designed to allow a rider to slide along the ground without serious injury, if a motorbike accelerated without control would it be practical for the rider to jump off? I expect that it’s a lot more practical than expecting a car driver to jump out the window…

    Charles: Thanks for the detail. In terms of what the driver can do it seems that the F1 system is very automated and therefore the driver can’t just press the clutch. But F1 is really so very different to road driving that it’s hardly worth comparing in terms of safety. I just mentioned it to show the benefits of automation.

    furicle: My experience in driving cars is that I get exactly one good press of the power assisted brake after turning the engine off. The second press has significantly less assistance and the third has almost none. A well trained person might press the brake and hold it down in such a situation with a reasonable result, someone who is not as well trained (and it seems that police advanced driving training is not adequate in this regard) would be likely to press it twice or more and lose.

    The article suggests that it would be extremely difficult to stop the car while it was accelerating hard. This is a powerful car with a big engine. Also please cite a reference for that Audi incident.

    I agree that you should be able to just whack it in neutral, but it’s hard to think of that quickly in an emergency situation. As I noted in this post I’ve been in a similar emergency situation and I failed to put it in neutral. I believe that I am genetically predisposed to being more rational in an emergency situation than the majority of the population.

    Peter: Please explain situations you have witnessed where speeds in excess of 10Km/h reverse or 130Km/h forward were required to avoid a collision.

  17. Matthew W. S. Bell says:

    F1 cars do not use automatic transmissions. They use semi-automatic transmissions—essentially robotic manual boxes. Big difference.

  18. Don Marti says:

    The clutch pedal is a beautiful piece of human/machine interface, IMHO. Unlike a kill switch, the accessories keep running and you can let it go to restore normal engine power to the wheels. (On the other hand, if you can’t handle your vehicle if the power steering and/or brakes go out, it’s too big. I have had to wrestle and stomp a big station wagon and a bigger truck when that happened.)

    Yes, depending on my budget I’ll either stick with used cars or take a trip to Europe to pick up a car. I did talk to a person who did that recently and the European price plus the European driving vacation was comparable to the US price.

  19. etbe says:

    Matthew: When it comes to not having a clutch pedal and having the computer decide when and how to change gears there is no difference between an automatic and a semi-automatic.

    Brendan: Thanks for the link. One thing to note is that turning the engine off is a really risky thing to do, when the engine is turned off you can’t steer the vehicle, and the ignition key can become stuck in the off position – when your car is parked you will hardly notice an occasional delay of 20 seconds to get the ignition key unstuck so many cars are driven with issues in this regard.

    If you put a car in neutral and it’s on a flat road then the speed will rapidly drop below 100Km/h from wind resistance. You only need to slow to about 60Km/h before it’s relatively safe to hit an electricity pole or other obstacle.

  20. etbe says:,0,7584950.story

    The LA Times has a good article about how to control a car that has a broken accelerator pedal.

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