I figured it was only a matter of time until this happened. I can't say I can think of anything really wrong with it right now. Evidence from a car air bag's electronic data recorder played a vital part in sending a drunk driver who killed two girls to prison for 30 years. Edwin Matos, 47, was drunk and speeding in a suburb near Fort Lauderdale, Florida when his Matos' 2002 Pontiac Grand Am ploughed into a car driven by a teenage girl who pulled out of a driveway into his path. Jamie Maier, 16, and her friend, Paige Kupperman, 17, were both killed instantly by the resulting crash last August. Matos survived. In court last month, Matos's lawyers claimed he was travelling 60 mph in a 30 mph zone. But data from the air bag's electronic data recorder showed he was travelling at 114 mph seconds before the crash. This evidence contributed to Circuit Judge James Cohn decision to sentence Matos to a maximum 30 years imprisonment when he was convicted on two counts of manslaughter for his crimes. The Judge also ordered Matos to pay more than $17,000 to the two girl's families for funeral expenses, AP reports. Data recorders in air bags can record a car's speed and deceleration and other data such as the pressure on a brake pedal at the time of a crash. An estimated 10 million vehicles in the US are fitted with such recorders, which vehicle manufacturers began putting in vehicles in the 1990s to test air bag performance. In recent year court prosecutors have begun using information from these data recorders, the existence of which most drivers will be unaware, in criminal prosecutions, AP reports. (Source: http://www.theregister.co.uk/content/55/31564.html)36 responses total.
Re #0: The 114 MPH figure seems rather unlikely; it would take most vehicles far longer than the length of a neighborhood to get to that speed, and the idea of the driver of a car surviving a collision at such speeds is incredible. Far more likely is that the reading was faulty, either due to a bad sensor or wheel spin; I bet I could get a car to read 114 MPH without going over 30, on dry pavement to boot. Not to excuse the convict, but basing the length of his sentence on the unvetted "testimony" of a piece of hardware not certified for forensic purposes seems more than slightly wrong. Garbage In, Garbage Out; if the typical sentence for a drunk driver who kills someone isn't also the maximum, I don't see that Matos should have gotten it just because of a number in a flash EEPROM. I hope that the use of such data taken by non-certified systems is appealed, because either the reliability should be assured by testing and comprehensive self-checks, or it should not be admissible in court. A question for anyone who disagrees with me: would YOU want to go away for 30 years because of someone's buggy code? Remember that much of that code is written by programmers considerably junior (in both skills and experience) to many of the people here, and the purpose for which the system is designed is quite a bit different from this application.
I agree with Russ on this one. I have real concerns about admitting those readings as evidence, given that the equipment wasn't designed for that level of reliability and accuracy, and we don't know what its failure modes are. Or how reliable it is.
>The 114 MPH figure seems rather unlikely; it would take most >vehicles far longer than the length of a neighborhood to get to that >speed, Nonsense; I can think of any number of roads where a driver could wind it out to 114 before being dumped into a neighborhood with plenty of driveways and a 30mph speed limit. I live on such a road. >the idea of the driver of a car surviving a collision at >such speeds is incredible. Incredible, perhaps, but certainly not improbable. Most people won't survive a 100mph+ crash, but some do.
The dead bodies cushioned the blow. Actually, one would have to know the details of what physically happened in the accident to know whether or not survival of such a crash was realistic... but I think it's certainly possible. Black box technology has been well developed over the years both for use in aircraft and, more recently, in automobiles. Black boxes equipped in race vehicles provide, for the most part, extremely accurate readings of things like speed, G-force, tire pressure, and so on. They have to--the amount of money tied up in what the black boxes say is actually quite high. I have no doubt that solidly developed black boxes can provide strong, accurate pictures of what was happening to a car prior to a crash. However, lie detectors do a good job of telling whether or not people lie, too, and black boxes need to be well proven before they should be used as court evidence. I have no idea what the pedigree of the black box in the car involved was. Any word on whether or not it was well-proven?
At what point in the drive train is the speed recorded in the "black box"?
An inertial accelerometer could be used to measure the speed - they've almost certainly got one in there just to help figure out when the airbag ought to be triggered. And hey, "airbags save lives", maybe that's how the drunk lived through the crash. Anyway, his real crime was driving drunk, and a simple & reliable test for blood alcohol would prove that.
I too agree with both russ and jmsaul on this, but only to a point. Sure this is new technology but so were fingerprints and blood typing at one point but they are pretty much accepted today. I also don't have much of a problem with a drunk driver surviving a head on collision with the side of a vehicle while the passengers of the vehicle hit on the side are killed to to the lateral acceleration if they didn't have the proper side impact airbags. And I suspect that no matter how you look at it the drunk's black box probably recorded something closer to 114mph than 60mph in a 30mph zone - ok, so he was only driving twice the legal speed instead of almost 3 times? He deserved what he got. On a side note, one of the neat things you can do with a piece of surplus USAF test gear that was originally designed to test missle warning systems on aircraft is to fire off the airbag systems of certain mercedes and other high cost automobiles. Originally it was fun to sit off the active runway and fire them suckers to see what the wingnuts would do. THe seasoned would figure "NFW" but the FNGs would do some really excellent aerobatics while dirty. So, with the proper electronics one may bloody the nose of someone parking, but how likely is that in real life or in this case?
Re #1: The wheelspin argument hadn't occurred to me because I assumed the 114 mph figure came from extrapolating from accellerometer readings, since the airbag control unit would have to contain an accellerometer to begin with. What I really don't understand is why it matters whether he was going 60 mph or 114 mph in a 30 mph zone. Either way it's a ridiculous speed to be going there. Re #3: How likely he would be to survive a crash at 114 mph depends entirely on what he hit. It's not the speed that kills you, it's the deceleration. Re #7: A friend of mine has a neat toy...a small Gunn diode transmitter and feedhorn connected to a 9V battery and a push button. It's amusing to hit the button as someone streaks by you on the freeway and watch them hit the brakes as their radar detector goes nuts.
The objection Russ raises are obvious enough that I'd expect any vaguely competent defense attorney to raise them too. I'd think that there would be a lot of evidence that would tend to distinguish between a 60mph crash and a 114mph crash. You'd expect that an expert examining the vehicles and the crash site would be able to make a pretty good guess about how fast the driver was going, and that you could present other evidence that would tend to suggest the car was going faster or slower, though it might not give an exact value like 114mph. In fact, I would expect that nobody would bother to check the airbag controller unless they thought the reported speed of 60mph didn't make sense. If I was on a jury, it'd be hard to convince me to convict on the basis of an airbag accelerometer without some substantial collaborating evidence. I bet it existed in this case. You certainly could survive a 114mph crash in the right conditions. Assume the victims were in a lighter car without side impact airbags, that maybe was already starting to turn after pulling out of the driveway, so it was a partially glancing blow. Many modern cars protect much better against front impacts than side impacts.
I did some web searching on how the "black box" works. It has an accelerometer that triggers the airbags and also writes to memory data for car speed, engine speed, brake actions, and other things. However all of these data are from 5 second before the activation of the recording. A lot can change in 5 seconds. What I was unable to find was how the vehicle speed is sensed. It is not by means of the accelerometer, as far as I can tell.
In my high school physics class, the Ann Arbor Police accident investigation people closed the street in front of the school one day and did a recreation of a fictional accident for us to measure. They taught us how they measured the speed of a car prior to an accident, as well as where the driver began trying to stop, by measuring skid marks left over from the accident, and then taking a car with the same mass and the same tires and skidding it in the same place. If the driver were really drunk I suppose there might be no skid marks, but that would presumably make the physics calculations easier. Rather than doing the full recreation, they could just calculate how fast an object of a given mass would have to be going to throw another object of a given mass a given distance.
Re #4: I doubt very much that you will find significant commonalities between air-transport "black boxes" (which are actually painted orange) and the automotive devices which bear the same label. They are designed for completely different purposes, and are vetted to radically different standards (if the latter are vetted to any standard at all). Re #5: Given that many of the vehicles so equipped probably do not have the per-wheel sensors used by antilock brakes, the only thing that the designer of a generic "black box" could use is the vehicle speed sensor at the transmission output shaft. Wheel spin can make the reading of such a sensor be radically wrong. Re #6: Sorry, Scott, but you haven't given that enough thought. The accelerations of interest to an air-bag trigger accelerometer are orders of magnitude larger than the rates at which a car can accelerate under its own power, and the quantization error and zero-point drift of the output would make it useless to try to integrate the value to measure speed. Re #8: Well, yes, 60 MPH is a ridiculous speed to be going in a residential area. The real question is this: is it just to give one drunk 30 years for killing two girls, and another one 10 years, because one of them had a number in an EEPROM and the other didn't? Somehow I do not feel safer as a member of the public if chronic drunks start driving older cars to avoid electronic finks and harsher sentences. (Hmmm... who just replaced an old Lincoln? With what?) Re #9: The reliability of most other circumstantial evidence does not depend on un-vetted software taking irreproducible measurements, and it's all but certain that the defense didn't have the money to subpoena the code and hire special masters to go over it for bugs. For more worrisome things, see the items which follow.
Depends on which black box you're talking about. Typical passenger car black boxes? Probably, yes. The racing versions are developed by teams like Ferrari with nine-figure annual budget devoted to a total of 17 two-hour races--those are considerably more advanced and have to deal with many of the same issues, though what they want to know has different functions.
Russ, you're making assumptions about the capabilities of accelerometers. You're also making assumptions about what standards are set for airbag systems... unless you've actually got some airbag design experience your assumptions aren't any more valuable than mine.
From what I've heard, car companies have been adding more monitoring functions to airbag black boxes in recent years. They're trying to collect data that will help them improve safety. I'm assuming, if they want their data to have any validity, they've thought about the issues Russ is talking about. I'm also assuming that a defense attorney would have thought of the same arguments, and that the black box data was either confirmed by other observations (examination of the crash scene, "speedometer slap", etc.) or concerns about its accuracy were addressed. I heard another news story today that gave a different figure than the 114 mph one, but I don't remember what it was.
Re #14: An assumption borne of broad experience in the industry, Scott. An engineering manager will try to squeeze out fractional cent savings per unit, because a tenth of a cent over the annual volume of a single car platform is several times his bonus. This means getting rid of any capabilities that aren't absolutely necessary for the designated purpose of the system; if you need to trigger the airbag between 5.0 and 5.3 G of longitudinal deceleration, you can bet that the system will not be designed to sense and integrate 0.01-0.1 G accelerations and may very well not be accurate enough to do anything so sensitive. Placement of sensors in vibration-prone areas may degrade accuracy further. If you want to hear an interesting story about eking out cost savings in automotive, pony up a beer and ask me about the Ford Corporate Switch.
So you don't have specific experience with airbag design, then.
I've always relied on fractional-cent savings to explain the more bizarre design shortcomings in cars I've owned. Like the Ford van that had no coolant recovery bottle, just a hose pointing at the ground.
Re #17: Are you arguing that you know the business better than I do? I got put to work on some software design specs once, but got pulled onto another project before I could get into the meat. I have more experience with stability enhancement systems, which do use accelerometers of much higher sensitivity. However, SES is only available as part of very high-end ABS systems; your generic "black box" is not going to have such data available.
This response has been erased.
Fix Or Repair Daily
Found On Road Dead
First On Race Day
backwards?
Driver Returns On Foot
I wonder if I may be acquainted with Mr. Matos.
A fellow with the same name contacted me in early
2001 from a programmer contracting office in
Boston. He ended up placing me at a job
assignment for 6 months. It got extended to 11.
The company is HQ'd in Fort Lauderdale and this
Edwin Matos ceased being employed there . .
around last August, maybe I can look up the
time frame. Strange thing, for emailing,
he was in the habit of using my grex address.
I guess I shouldn't be surprised to not find
his employer's name in the news stories.
Re #18: That used to be standard on everything. So were vacuum motors to run the windshield wipers. Coolant bottles and electric motors are the modern improvements (some mandated by law, some not).
Re Russ's #19: Russ, I'm arguing that we're both making assumptions, and that unless you've got ACTUAL experience in airbag design your arguments don't trump mine. OK, so now we know you've worked with accelerometers. So have I, at MSU's Agricultural Engineering dept (employee, not student).
Re #20: No, Ford was neither supplier nor customer for that project.
Re #22: I realize coolant recovery bottles are modern improvements. But I considered a 1990 model year van to be "modern". My '85 Crown Victoria had a recovery bottle, as does my '82 Volkswagen. Eventually I got sick of it pissing coolant onto the ground on hot days and bought an aftermarket bottle.
Re #23: If you have no experience with the cost-driven nature of automotive design practices, you don't really grasp the issue. Claiming that someone else's experience isn't exactly the matter at issue (therefore you are correct) is special pleading; air bags are made by suppliers of broad lines of automotive components, all product lines are under identical cost pressures, and they swap engineers and managers all the time.
Russ, unless you've got SPECIFIC EXPERIENCE in airbag design your assumptions are NO BETTER THAN MINE. I realize you've probably got a lot of emotional investment in "I'm smarter than everybody esle" but you really need to accept that it might not be true.
Re #25: Lots of improvements mandated for cars were not mandated for "trucks", and vans are legally "light trucks". I don't know why a van owner wouldn't want to keep free oxygen out of the cooling system and the other benefits that a coolant recovery bottle provides, but it's possible that the space constraints under the short nose of the typical van (plus the cost) kept the manufacturers from offering them for a few years. Hey, the radiator replacement comes after the warranty expires, so why should they care? </cynicism>
(Cluelessness: Using an argument immediately after being told exactly why it is fallacious.)
(Obstinance: Pretending to be an expert, even after having to admit one has no special knowledge or experience in the relevant field)
Re #30: Yeah, but when are you going to admit it to yourself? Just for the audience, the issue is whether the airbag-trigger accelerometers are used to feed data to the "black box" used to get information on airbag performance. Scott is claiming that a system which is absolutely required to produce a binary fire/ no fire (or a trinary no fire/slow/fast) indication at an acceleration of several gravities will either be suited to measuring and integrating accelerations of a small fraction of a gravity, or have its design broadened to accomodate the additional functionality (at some cost in better sensors, more computing power, and more complex and thus expensive testing requirements). That's what it would take to get meaningful information during the period before the actual collision. I'm asserting that this is contrary to automaker design practice in all regimes, including safety-critical systems such as brakes. (BT, DT, GTTS.) The automaker's preferred method of capturing speed data would be to read the speed-sensor packets going over the vehicle bus, at zero cost; the bus interface is required to capture other data, and is far more standard across platforms.
Russ, you're making bad assumptions about my position. I'm claiming that it's possible, not that the automakers would spend extra money on a complete implementation. Although it's also possible that the automakers, for CYA purposes, indeed spend extra to have accurate acceleration/speed data.
Hmm. I do know that it is possible given knowlege of the make and model to trigger the airbag of many a parked car using a 5lb sledge appropriately applied. Think thunder storms and car burglar alarms for another and similar example.
Re #33: I'm not sure car alarms are a good example. The culprit in a lot of cases seems to be "window break detectors" which are really just "loud noise detectors". For some reason (maybe so the owner feels like the alarm is "doing something") these suckers seem to get cranked up as far as they'll go when the alarm is installed.
Re #32: The automakers are interested in statistics, which wouldn't be hurt by a substantial fraction of data known to be unreliable and thus discarded. (How many hundred air bags go off every day?) Forensic purposes require accurate data every time; it is an essential conflict between the requirements of the base system and the very different uses to which its output is put.
I don't think Scott is claiming to be an expert. Scott is claiming that neither he nor Russ are experts.
You have several choices: