Breathalyzer Source Code Revealed 501
Nonillion writes "New Jersey attorney Evan M. Levow was finally able to get an order from the Supreme Court of New Jersey forcing the manufacturer of the popular Draeger AlcoTest 7110 to reveal the source code. Levow turned the code over to experts, Base One Technologies, to analyze. Initially, Base One found that, contrary to Draeger's protestations that the code was proprietary, the code consisted mostly of general algorithms: 'That is, the code is not really unique or proprietary.' In other words, the 'trade secrets' claim which manufacturers were hiding behind was completely without merit." Following up an earlier discussion here, the state of Minnesota has (without explanation) missed a deadline to turn over the code for a different breathalyzer.
"code" is probably in the hardware (Score:2, Interesting)
Re:"code" is probably in the hardware (Score:5, Informative)
You don't seem to have read the "article", but then again this is /.
Even in such a simple case there are many things it should be testing. Is the A/D output sane? Does it take 3 quick samples while someone is blowing and average them or just take it once (which could be wrong for some reason)?
According to the article, it doesn't look like it does. It calibrates the wind sensor, but doesn't check that the calibration is sane. It doesn't report errors unless they happen 32 times in a row. It disables the watchdog timer. It disables the interrupt for illegal instructions. It doesn't meet any coding standards. It contains code with things like "this is temporary for now" in it.
There is an obvious reason why they didn't want the code released.
Re:"code" is probably in the hardware (Score:5, Insightful)
I have an even more important question: Does the friggin' device work? I agree that reading through the observations, the code doesn't instill confidence. But the real important question is whether or not it works. There must be some requirement as to how many false positives/negatives are allowed because no matter how good your code, nothing is infallible. So what is the requirement in terms of acceptable false positives and/or false negatives, and does the device meet that requirement?
Is there is a real and legitimate belief that this device doesn't work? Or is this just some escapade launched by an attorney to free a guilty drunk driver?
Re:"code" is probably in the hardware (Score:4, Informative)
Of course, by the time they actually bring out the breathalyzer, they've probably already decided to arrest you based on the Nystagmus test. Most of the procedure is just misdirection to keep the suspect calm, thinking he still has a chance to avoid arrest, even though it's already a foregone conclusion. It gives the DUI suspect a chance to dig a deeper grave for himself... The breathalyzer result is more valuable for getting confessions in the field, rather than for evidence in court. They don't actually *need* mechanical sobriety tests, since HGN, one-leg-stand, walk-and-turn tests and the like, stand up just fine in court.
Re:"code" is probably in the hardware (Score:5, Interesting)
When I got back to the station to take the real breathalyzer, I brought to the attention of the police officer that the breathalyzer I was being tested on had a 2 year old calibration sticker. He said, and I quote "oh don't worry these machines are accurate to 10%!". Long story short, it said my BAC was
The police will lie to your face so you think you're going home, write down what is necessary to create probable cause(1) and screw you while you smile. What do you expect from a state that pulls in $800k a month from DUI fees and I'm sure many times more than that in corrections fees?
1) I was pulled over for having a cracked tail light. I volunteered to do a field sobriety test including walk & turn, 1 leg stand, HGN. Walk & turn, I did flawlessy, state patrolmen even admitted it. One-leg stand, I made it to 45 seconds and only put my foot down once. The policeman wrote in his checksheet that I used my arms to balance myself and in the notes field wrote that I also kept my hands in my pockets because it was cold.
Long story short... If you get pulled over and you have had even 1 drink, say these works: "I respectfully decline to provide any type of field sobriety test to you at this time. If you desire, I can accompany you to the nearest station for a breathalyzer as agreed when I received my drivers license."
At that point, they must decide if their probable cause is worth the pain in the ass you are being. Although another recent story on
Re:"code" is probably in the hardware (Score:4, Informative)
That said, some people can ping 0.080 after only 1 drink, about 40 minutes after finishing that drink. If you had just finished your 3rd beverage, got in the car and then got pulled, after 3 drinks you could easily have been 0.08+. That fact that a second Breathalyzer confirmed this means you were guilty. Also, start counting the 3 hours from a point about 15 minutes after finishing the first drink, not from the time you got to the place to start drinking... You might see a different picture entirely there.
If you have even a half-assed lawyer, and you bothered to get the ID numbers of both breathalyser used, and both had not been calibrated withing their required term (or failed calibration testing) then you would be let go without a fuss. My guess, at least one of the 2 units was within normal parameters or would pass calibration anyway, and thus be admissible in court.
Fact is, at 0.08, you're impaired enough for it to be easily detectable in visual and reaction simulators. In fact, many states are arguing, based on scientific evidence, that this should be lowered to 0.06 as there is noticeable impairment at even that level. 0.06 means if you have 1 drink, 90 minutes later you could still fail.
As for NHTSA recommendations on field testing, that's it, they're recommendations. Officers are expected to use their own best judgment on how to test a person. The NHTSA is more concerned with the type of test and teaching officers how to recognize signs of intoxication. On the other hand saying "Are we done yet?" probably just pissed him off...
If you have 1 drink, you're probably OK, more than 1, you're at serious risk for DUI. Also remember, Corona is slightly stronger than say Bud Light. A Guiness is nearly twice as potent. A glass of wine is supposed to be 4 ounces, and is measured at 10% abv, but find me a restaurant that doesn't pour at least 6 oz glasses with 11-15% wine...
Some foods can accelerate or slow the absorption as well. The first drink probably went right through you, but if you were eating food during the second and third rounds, both of them may have entered your system concurrently through digestion.
Lessons learned here: 1, don't drive with a cracked tail light (and always use turn signals). 2, accept the field test, but decline the breathalyser. If you did bad enough on the field test, you'll go to jail anyway for a breathalyser or blood test, but if you're clean, you're OK, unless you piss off the cop or have a bad day. At the station, refuse a breathalyser and respectfully request a blood test on the grounds that it is more accurate. (if you failed a street sobriety test already, this might buy you a night in jail while you wait for results, but again, if you're clean, there's no worry) 3, never say "are we done yet" to a cop. Be polite, never act like you're in a rush. (and know his rank! This goes a long way!!!) 4, don't drink and drive... (drink at home, it's cheaper!) 5, if the calibration sticker is out of date, refuse the test and demand to have a supervisor come to the roadside site (it's your right to do so, though he may choose to bring you to the supervisor instead. this also goes for speeding tickets if the radar was not calibrated immediately before you were clocked with a tuning fork displaying a matching serial number to the radar). The more you know about the requirements the officer must display in the courtroom, the less likely you are to get a ticket. 6, have all your paperwork (registration, insurance, etc) neatly file
Re:"code" is probably in the hardware (Score:4, Informative)
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Re:Article seems biased (Score:5, Insightful)
Considering this is shipping code in a device that doesn't exactly do automatic updates over a wireless network, I'm not sure when, exactly, you're anticipating that this testing" code will be replaced with the "real thing". You'll forgive me for thinking you're taking a fairly blase attitude towards the obviously complete lack of coding standards, formal oversight, or rigorous vetting in code that can quite literally destroy someone's entire life based on the output.
Playing around with temporary hacks is fun for a shareware app, not an officially-sanctioned law enforcement device that decides whether you were the victim of an accident or the perpetrator of a felony.
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You could release the device with a non-optimal but completely functional piece of code due to time pressures in the development schedule. Maybe it's slow, or memory-hungry, but it still does the job just fine.
You mark the code as "temporary".
At a later date, you decide to release a new
Re:"code" is probably in the hardware (Score:5, Informative)
- Several sections are marked as "temporary, for now"
- Converters will substitute arbitrary, favorable readings for the measured device if the measurement is out of range
- The software takes an airflow measurement at power-up, and presumes this value is the "zero line" or baseline measurement for subsequent calculations. No quality check or reasonableness test is done on this measurement
- It would fail software standards for the (FAA) and (FDA), as well as commercial standards used in devices for public safety
What is this thing, alpha?Re:"code" is probably in the hardware (Score:5, Insightful)
Flip it to another tool used for criminal convictions: if DNA were a public, proprietary process through only two or three companies nationwide and they refused to show anyone how it worked, would you trust them? Absolutely not.
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I know I'm going to be torn apart limb by limb by the modders out there, but yes, you're right. The hard limit isn't really the point. Do you think people are suddenly dangerous over 0.05 (or whatever the limit is in your neck of the woods)? The point is that you've been drinking before you've been driving, and you really shouldn't have been doing that. That's what the law is intended to do: to stop you from
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First off, I don't drink - never mind drinking and driving. And personally, I think that truly incapacitated drivers (not just Alcohol) that put others at risk should be jailed for a very long time. After all, killing someone lasts a lifetime.
That being said, laws should be enforced properly, and evidence should be good. If driving at 0.04 is bad, then that's where the limit needs to
Re:"code" is probably in the hardware (Score:5, Insightful)
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Re:"code" is probably in the hardware (Score:4, Interesting)
To prove the photo was legit...not double exposed maybe (taken when yellow, but, redlight shown), to make sure the yellow light was sufficiently long (there have been cases showing that yellow lights were shortened on purpose to generate more fine revenue)....things along that line.
Re:"code" is probably in the hardware (Score:5, Informative)
Consider, for instance, if radar guns reported "91mph" any time they detected too high a value (say, above 200mph). You could be driving by at 75mph, some malfunction could cause the gun to detect 600mph, it would report "91mph", and you'd be screwed. If it reported 600mph and you got pulled over based on it, you'd probably win in court because your car can't do 600mph.
Re:"code" is probably in the hardware (Score:5, Informative)
This is why it's always vitally important to get a true blood test, and to preserve a sample for your attorney.
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On the contrary, insist on the breathalyzer and contest the results if you fail. If you fail the blood test, you're screwed.
Re:"code" is probably in the hardware (Score:5, Informative)
I've posted this type info before...on other stories, but, depending on the state you are in, if you know you're gonna blow over the limit....refuse ALL tests...don't blow anything, don't give blood....and for God's sake...don't get out and try the field sobriety tests. All those do, is let the cops collect evidence to be used against you. According to my atty....he said you know you're going to jail no matter what...don't help them gather evidence from you. Just don't say anything, and put your hands out for the cuffs. And call the lawyer immediately....
I know if varies from state to state...but, in many (maybe most) you probably will lose your license automatically for a year, but, can often get a hardship license for getting to work, food, etc. You may get a reckless driving...but, at least it isn't a DWI. That can hurt your credit, and job possibilities in this day of the MADD witchhunt. The new ridiculously low BAC forced by the feds (0.08) can get you nailed even if you are fine to drive.
Anyway, if you like to have a drink out at all...you should know the laws of your state...and be prepared...
How about this... (Score:3, Insightful)
Like calling a taxi or getting a designated driver?
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The crazy shit won't stick in court? Where the hell do you live? I have lived in Jersey, Georgia, Tennessee and a bunch of other places while in college and in the Air Force and law enforcement officers at all levels are the same; they are a bunch of sleazy lying bastards. They will charge you with all sorts of crazy shit because they know that a judge will side with them on at least half the charges no matter how crazy of a story they make up or how good of an attorney you get to represent you.
In the US
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Or just think ahead and don't drink if you're planning on navigating a massive structure weighing thousands of pounds down a highway with fellow human beings. Have a designated driver. Walk home. Take a cab. Driving isn't your only option.
Rather than making this an exercise in what you can get away with within the law, make it an exercise in personal responsibility in regards to your fellow ma
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It's pretty funny, actually. All this witch-hunting, when all you really need is to stick a few cops at the local bars right after last call.
All the MADD BS distracts from the actual dangerous drunks - you know, the ones with multiple DUIs for .15 and no license. Toss them in jail and be done with it.
Personally, I always walk to the bar, because I know full well I'm going to be utterly illegal to drive when I walk out.
So they can pop you for drunk in public, whee. Cops are out of control - going afte
Learn something new every day (Score:5, Funny)
Shocked (Score:5, Funny)
Let's whiteboard this people (Score:5, Funny)
goto JAIL;
}
Re:Let's whiteboard this people (Score:5, Funny)
goto JAIL;
} else {
collect(200);
}
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Gotos considered harmful (Score:5, Funny)
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Undefined symbol: collect().
Undefined symbol: rich.
'rich' used without assignment.
Undefined symbol: recieveBeating().
Undefined symbol: jailRape().
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Do it up in Ruby and create some Jail class from which you can create jail objects. Okay, I'm going to stop.
Trade secrets claim is valid (Score:3, Insightful)
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Sorry, you can't hide behind a "trade secret". (Score:5, Interesting)
Then what DOES make something a trade secret? The mere fact the software is compiled and/or programmed onto a chip? An EULA? An"anti-circumvention device" as defined by the DMCA? Seriously, where should we draw the line with "trade secrets" when it comes to protective legislation? The only "trade secret" revealed here is the fact that the manufacturer in question embedded alpha-quality software in a product released to production. That sort of a "trade secret" is generally considered willful negligence or fraud.
It still takes significant engineering/test/validation effort to get to a working device.
It is apparent that little to no such QA was done on this particular device, which to me sounds like a grave mistake considering the device is trusted to keep drunk drivers off the road. Keep in mind that this device is theoretically able to report just as many false negatives as false positives, do not only would it be possible for a sober driver to be falsely charged with a DUI (as this lawyer claims) it is also possible that countless drunk drivers falsely blew UNDER the limit and were allowed to continue on their way and put others in harms way. That could be considered criminal negligence on the part of those who engineered this device.
Just because it takes effort (in time and money) "to get a working device" even when there is nothing novel in its functionality does not mean that those putting forth the effort should be able to hide from scrutiny behind a "trade secret". The systems I work on are sometimes involve safety interlocks. My employer subjects their software division's development practices to audits from government agencies. Our clients often stipulate that they must have access to source code (though since we are a closed-source shop we never grant redistribution rights). Even if there are novel implementations or "trade secrets" there are legal instruments to accommodate for them and still remain accountable.
These "breathalyzer" devices used in the field are far from trade secrets--I remember plans for one in Radio Electronics years ago that was said to be quite reliable as a preliminary measurement device (didn't report a specific value, but had a "traffic-light-interface" of 3 LEDs). The "trade secret" excuse is flimsy and shameful. It is worse than the whole Diebold voting machine debacle because it can directly affect a person's safety and well-being.
Re: (Score:3, Informative)
Then what DOES make something a trade secret?
According to the Uniform Trade Secrets Act [upenn.edu]:
(4) "Trade secret" means information, including a formula, pattern, compilation, program, device, method, technique, or process, that:
(i) derives independent economic value, actual or potential, from not being generally known to, and not being readily ascertainable by proper means by, other persons who can obtain economic value from its disclosure or use, and
(ii) is the subject of efforts that are reasonable under the circumstances to maintain its secrecy.
Now in this case the algorithms in the breathalyzer code are generally known to the rest of the industry so the likelihood that the code contains trade secrets is pretty low. If the breathalyzer used a revolutionary, and probably patentable, method to measure the blood alcohol level then the code would be covered under the Uniform Trade Secrets Act and other relevant civil law.
It's very likely that the breathalyzer manufacturer is just using the concept of a tra
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The way I read that, it's protectable as a trade secret, because they can make more money selling the thing if they keep the crappy code a secret - if it gets leaked, they could lose a lot of sales if anyone cares about quality.
DUI laws are just the second coming of prohibition (Score:3, Interesting)
PS People who drink and get into accidents should be prosecuted as if they had reckless intent.
Re:DUI laws are just the second coming of prohibit (Score:2)
Damn lies and statistics. (Score:3, Informative)
Comment removed (Score:5, Interesting)
Re:DUI laws are just the second coming of prohibit (Score:2)
Re:DUI laws are just the second coming of prohibit (Score:5, Insightful)
Worse, it won't even be near to possible for them to indentify all of the sufficiently impaired so as to protect the rest of us from their idiocy.
What drunk driving laws do is create an incentive for everyone to voluntarily police themselves, and to act more responsibly. If you know you run a risk of a long incarceration just for drunk driving, you may not take my life into your hands by getting behind the wheel and driving the same roads as I do. If you (or most of these drunk idiots) know that the only penalty for getting caught is being taken home, then you'll be much more encouraged to just take your chances with my life, rather than deal with the inconvenience and cost of a taxi ride.
Drunk driving laws disencentivize behaviors on an individual basis that normally have unfortunate incentives on an individual basis, but have an extremely high average cost for the rest of society. This is also why no-sleepy-driving and no-cellphone-driving laws are a similarly good idea.
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In California, for example, police statistics have shown that crash rates did not go down when stronger DUI laws were enacted. Inherently, driving a vehicle is the dangerous activity.. drink driving just gives people an acceptable scapegoat.
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It sounds like you're saying that if you walk down a street, randomly firing your automatic weapon in all directions that the cops should be allowed to disarm you and send you on your way, but you shouldn't be charged with anything unless you actually hit someone or damage something.
Anyone w
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And, I agree with you it is a criminal act that should be punished after a day in court.
HOWEVER,
We are not talking about the guys who are falling down smashed can't get the key in the door drunk.
We are talking about folks at
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To which my wife replied "It's not illegal to get pissed drunk and take a gun and go hunting... well at least I don't think it
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Cause that's about how stupid your argument is.. if you can't participate in an adult debate without making stupid analogies or appealing to emotional crap, don't participate.
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That's not a very good argument.
Oh really, let's look at yours then.
Driving under the influence of alcohol is illegal.
Huh? What does current law have to do with what is right?
Therefore, doing it is breaking the law regardless of whether or not you injure someone else.
No shit, that was my argument.
We can add on to that that driving is a privilege, not a right, and that every driver has a responsibility to drive safely.
Uh huh. What makes you think that? Current law? A car is property. I have a right to use my property. If you want to say something like "who is and who isn't allowed to drive on public roads is at the discretion of the public" then I'm willing to accept that assertion, but it seems to me that such a thought never entered your mind.
Impaired driving (without regard to the source of impairment) is inherently unsafe and puts everyone else on the road at risk of injury or death.
So, for example, disabled people shouldn't be
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Driving drunk just makes it slightly more dangerous.
People would have you believe that there was some massive drop off in the number of crashes on the road when DUI laws were enacted. There wasn't.
Mod Parent up! (Score:3, Insightful)
So moderators - stop attacking the messenger ok?
There is a TV program which I do not watch called "Canada's worst drivers".
This program apparently is oriented to rehabilitating some of the
So you can't refute his arguments. Gotcha. (Score:2)
Re:So you can't refute his arguments. Gotcha. (Score:4, Funny)
How to really make the roads safer. (Score:3, Insightful)
As much as I hate to agree with the gp, there is a valid point there, even if calling prosecution of drunk driving modern prohibition is absurd. The valid point is that there are plenty of things that make drivers unsafe and the tests to determine competency are arbitrary. Blood alcohol content doesn't measure competency, it just measures a risk factor, of which there are many including age, rest and mood which are ignored. On any given day, despite the fact that I don't ever drive drunk, there is some reas
The reason MN doesn't have the code (Score:5, Interesting)
I represent three clients in Phoenix, AZ, who have been trying to get the code from CMI for the same reasons, and have been met with nothing but frustration. Fortunately, a couple judges here have agreed with the defense that examination of the code is necessary to mount a defense, under due process grounds. We (myself and a number of other attorneys) have had dismissals in a total of about 11 cases in the City of Phoenix, all of which are being appealed. There are a few cases in superior court that will be appealed shortly as well. It's been a busy time in the world of DUI litigation.
Unfortunately, many judges here do not see the relevance. Further, they have enacted legislation to prevent the preclusion of breathalyzer results, despite the inability to examine the "schematics or source code" of the machines.
Believe me when I tell you - these machines are unreliable, and subject to many errors, most glaringly the result of RFI screwing up the results. I've read the findings of the independent lab on the NJ case, and it does raise many concerns. My biggest problem is that law enforcement can essentially hide behind a foreign corporation, and a jury never hears about many of the problems at hand.
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I'm actually a bit surprised that this isn't the case in america.
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Are you at liberty to say why RFI is considered the most glaring fault? I wouldn't expect this behaviour from a breathalizer, so it kind of surprises me.
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Indeed, wouldn't the simple fix for the Legal system to mandate blood sampling as a secondary test. That is, the on the spot device could only be used to determine who should have their blood sampled. Of course, anyone refusing to have the blood test would be back in the position of being potenti
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Re:The reason MN doesn't have the code (Score:5, Interesting)
You don't have to take a breathalyser or do any road side test. And in fact you shouldn't. Even if you have been never tell the cop you've been drinking when pulled over.
What you do have to do is submit to a blood test at a hospital if the suspect you of drunk driving. If you don't then you'll lose your license.
Here's some advice if pulled over:
When asked if you've been drinking, say no. They always ask this question a night. If you say yes you've had one or whatever, you are a suspected DUI. They usually won't smell things on your breath or whatever. Just say no and they'll probably just ask to run your license and give you a speeding ticket. Unless it's obvious you're drunk
When asked to get out of the car, comply. You have to. If they ask you to do ANY roadside test, decline. You will be pressured here. Simply say your lawyer informed you to never do a roadside test under any circumstance. The cop will evaluate you at this time. One of 2 things will happen now.
If you're borderline and seem to be "normal" or not very drunk, they'll probably let you go with a ticket. They realize that it will be a waste of their time to arrest you take you down to the hospital, file reports, etc only to find out you are at
If you're obviously drunk, they'll take you down confidently knowing you will fail the test and be charged. But that's the price you pay for driving when sloshed.
The keys: Never admit to drinking anything. This can only hurt you. Let your lawyer do the talking. Refuse any roadside test. They can only hurt you. Cooperate and take a blood test. Potentially an hour or more after you've been pulled over. You will invariably be more sober than when you were pulled over. This works to your advantage.
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Please excuse my terrible decimal writing there. It is meant to say a a
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Now, when you say breathalyser, are you talking about the roadside one or the station one? There's quite a difference.
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There are two things that bother me about the discussion of what percentage of accidents are alcohol related. The first has be
Re:The reason MN doesn't have the code (Score:5, Insightful)
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The MADD crew lost the moral high-ground long ago.
BS statistic warning! (Score:3, Insightful)
Well there's a surprise.
Did you know that the percentage of accidents near football stadiums involving football fans is shortly before and after football games is five times the percentage at other times? Quick, ban football! Being a football fan causes accidents!
So between 2 and 3 AM, twice as many accidents involve alcohol as during the rest of the day. Do you think MAYBE, just MAYBE, that might be becaus
Re:The reason MN doesn't have the code (Score:4, Insightful)
you have NEVER EVER had a beer at work (maybe some milestone or something) and then drove home, perhaps even a few hours later?
that never happens to you?
or you have a glass of wine out on a date?
the laws are too harsh and people DO need to know all the info that the other side knows. not only is it desirable to know all your rights, its -necessary- for the system to really work at all.
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That's not the case in Arizona.
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It's also enough to have you arrested instantly, as refusal to take a breathalizer is considered and admission of guilt.
Couple problems with that (Score:2)
This is especially true because unfo
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This isn't much different than the magical IP_address->User_Name that RIAA has been using. If courts begin tossing out cases, or at least disallowing these technologies as evidence, then a foot is going to fall somewhere.
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From the sound of it, it would be trivial to bring the code up to snuff. Only a few months worth of work for a software engineer or two. I think the state should have a DER (Designated Engineering Representative) which audits the source code and development practices of these equipment manufacturers (radar guns, breathalyzers, etc).
I definitely think that
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Also, you refer to it with the propaganda word "drunk driving". To be over the limit doesn't mean you're drunk. In fact, plenty of people could have a
Trade Secrets (Score:5, Insightful)
If they were expecting their code to be opened to the public, they would have taken the effort to fix up "spaghetticode.inc" which contains the single comment "//This works though i'm not sure why... clean up l8r!!!!".
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The entire 12 problems (Score:5, Informative)
1. The Alcotest Software Would Not Pass U.S. Industry Standards for Software Development and Testing
2. Readings are Not Averaged Correctly: When the software takes a series of readings, it first averages the first two readings.
3. Results Limited to Small, Discrete Values: The A/D converters measuring the IR readings and the fuel cell readings can produce values between 0 and 4095.
4. Catastrophic Error Detection Is Disabled: An interrupt that detects that the microprocessor is trying to execute an illegal instruction is disabled
5. Implemented Design Lacks Positive Feedback: The software controls electrical lines, which switch devices on and off, such as an air pump, infrared source, etc. The design does not provide a monitoring sensory line (loop back) for the software to detect that the device state actually changed. This means that the software assumes the change in state is always correct, but it cannot verify the action.
6. Diagnostics Adjust/Substitute Data Readings: The diagnostic routines for the Analog to Digital (A/D) Converters will substitute arbitrary, favorable readings for the measured device if the measurement is out of range, either too high or too low.
7. Flow Measurements Adjusted/Substitute d: The software takes an airflow measurement at power-up, and presumes this value is the "zero line" or baseline measurement for subsequent calculations.
8. Range Limits Are Substituted for Incorrect Average Measurements: In a manner similar to the diagnostics, voltage values are read and averaged into a value.
9. Code Does Not Detect Data Variations
10. Error Detection Logic: The software design detects measurement errors, but ignores these errors unless they occur a consecutive total number of times
11. Timing Problems: The design of the code is to run in timed units of 8.192 milliseconds, by means of an interrupt signal to a handler, which then signals the main program control that it can continue to the next segment.
12. Defects In Three Out Of Five Lines Of Code: A universal tool in the open-source community, called Lint, was used to analyze the source code written in C. This program uncovers a range of problems from minor to serious problems that can halt or cripple the program operation.
Sorry if this is redundant, I didn't see it listed anywhere that I could tell up front. If you note that list is pretty serious. They picked a "top 5" type thing for the other link, but this one is pretty accurate. Note these guys were called in as expert witnesses and their information on their website shows they have extensive experience working with government. If these guys find flaws that is definitely pretty serious.
My problem with the 12 problems... (Score:2)
The first po
Re:My problem with the 12 problems... (Score:5, Informative)
Take 3 readings, say 1 2 3 for the sake of argument. The text says the first two are averaged, so:
(1+2)/2 = 1.5
Now this average is averaged with the third reading
(1.5+3)/2 = 2.25
or in full
((1 + 2)
Note the 3rd point is weighted twice that of the first 2 (i.e, its divided by 2, the first two points are divided by 4).
The real average should be:
(1+2+3) / 3 = 2
but the last point is being weighted more in the incorrect version so the average was given as 2.25
If the first point was weighted more you would expect the average to be less than 2.
Re: (Score:3, Informative)
While I applaud you for admitting your error, as most on /. never will when called out, you're being overly pedantic about the mean-average relationship. The arithmetic mean is a type of average, so technically, yes, the mean is an average. There are different kinds of averages: mean, median, and mode specifically. But it is incorrect to say the mean is not an average, just as it is incorrect to say that a square is not a rectan
Re: (Score:3, Informative)
Of course it really makes a difference what they mean when they say that successive readings are averaged in. For example, if they averaged the first 2, and stored the result, and then average
Re: (Score:2)
Here's one for the mythbusters... (Score:4, Funny)
So, if I blow into the device as soon as it boots, I will always be tested negative??
This is important (Score:5, Informative)
Without measures like this, police brethalyser selection is distorted by powerful confirmation biases.
Given an honest belief that suspects that are given the brethalyser test are intoxicated, the natural selection bias is towards machines that read positive more often. Even without a single thought of "we need a machine that convicts regardless of guilt", that's what they will tend to get.
Allowing the defense to face the actual witness (the brethalyser) so to speak provides the needed negative feedback to drive selection back towards accurate impartial instruments even if only to make DUI charges stick in court.
More to the point, it can drive machine selection towards those that meet the beyond a reasonable doubt standard. If trials are going to favor the readout on a brethalyser, the machine should (for example) always round towards a lower reading when measuring or computing. For example, if there is any noise in a reading, the lowers is beyond reasonable doubt, the average is vaguely justifiable (though it is probably closer to a preponderance than it is beyond reasonable doubt) and the highest is just plain trying to get convictions regardless of merit. Otherwise it has the potential to accuse someone of DUI (to the extent that a machine can accuse) even if in fact componant tolerances may mean the difference between just over the limit vs. just under. After all, the machine is not suceptable to a jury judging if it seems unsure or knew it was close to the edge based on testimony.
A surprising number of measurement devices meant for scientific and medical purposes (as well as law enforcement) do NOT correctly handle significant digits, error bars, or rounding. Many programmers do not understand the importance of different rounding rules, and even think that add .5 then truncate is always correct.
Roadside results are not important, anyway (Score:4, Insightful)
But in the end, I don't think any of this matters. Drunk drivers are not prosecuted based on roadside breathalyzer tests. They are prosecuted based on tests done back at the police station using either a blood test or a much better lab-quality breathalyzer. These instruments are regularly tested in a way that makes it easy to convince a jury of the validity of the results. I've seen some of the corresponding tests on a roadside breathalyzer, and they convinced me not to trust the device.
So, it's good advice to decline the roadside tests.
Actually... (Score:4, Informative)
A heated-wire anerometer works by running a current through a wire and measuring the voltage drop through the wire. The resistance will change with the speed and specific heat of the substance you're passing across the wire, because the substance will cool the heated wire based on a number of factors. A breathalyzer simply eliminates the speed measurement, and the other measurements, and what remains is the specific heat of the substance passing through the device. They simply run a reference gas in the opposite anerometer, and take the differential, and the alcohol will give a certain value.
Not a trade secret, unless something being common knowledge for all instrument engineers taught in the past 40 years is a trade secret.
That would flunk any lab's requirements! (Score:4, Interesting)
Re:Frosty Pist (Score:5, Funny)
Processing... Processing... Done! (31 errors ignored)
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Re:Frosty Pist (Score:5, Funny)
There. Fixed it for you =]
Re:Frosty Pist (Score:5, Funny)
Re:Frosty Pist (Score:5, Insightful)
Re: (Score:3, Informative)
from http://www.duiblog.com/2007/09/04/secret-breathaly zer-software-finally-revealed/ [duiblog.com] - 10. Error Detection Logic: The software design detects measurement errors, but ignores these errors unless they occur a consecutive total number of times. For example, in the airflow measuring logic, if a flow measurement is above the prescribed maximum value, it is called an error, but this error must occur 32 consecutive times for the error to be handled and di