17 ms·

Researchers say a breathalyzer has flaws, casting doubt on countless convictions

133 points by uptown 9y ago

nerdponx 9y ago
Remind me again why a device paid for with public funds and used to carry out essential public functions of the government should be anything but open source.
- sigstoat 9y ago
  the government buys some of very nearly everything and uses them to carry out essential public functions. you've got to have a better criteria than that.
  - logfromblammo 9y ago
    The defense in a criminal case has the right to examine witnesses that presented evidence against them. When the witness is a machine, such an examination must necessarily include inspection of the operating protocols, technical specifications, calibration records, and source code. Forcing the defense to ask for it in discovery for every single case seems somewhat counterproductive. If your code is being used to put people in prison, you don't get to keep your trade secrets privilege.
    - alistairSH 9y ago
      It is counterproductive. It's also a feature of the system. At best (for the accused), thousands of dollars get spend on defense, pumping money into pockets of lawyers. At worst, the accused can't afford this level of defense and the DA gets another notch in their belt.
- jpdb 9y ago
  Because the software/IP isn't owned by the government. I'd personally rather the US government pick the best solution, not the most open source one. I would hope the best solution is open source, but the gov't shouldn't be forced to sacrifice quality. However, I can agree that any Software/IP developed via public funds should definitely be open source.
  - DennisP 9y ago
    Define "best." My definition would be something that's not only accurate in most conditions, but lets the accused mount a meaningful defense. Comprehensive testing by an independent lab gets us partway, if all the results are available to the defense, but it's better if we can both do black box testing and examine the code.
  - thatcat 9y ago
    How should the public verify the government has chosen the best solution if the design of the solution isn't readily available? Depending on your perspective and definition of best, faulty designs that give more favorable results could deliberately be chosen to increase revenue / crime stats.
  - jononor 9y ago
    Trustworthyness is (or maybe should) be an criteria for things being used to provide data for legal matters. Being able to independently verify the device is critical for this, and open-source makes this easier.
  - craftyguy 9y ago
    > I'd personally rather the US government pick the best solution, not the most open source one. I'd personally rather the US government consider trustworthiness, which is only afforded in open source projects, to be an important criteria for "best solution."
dbrgn 9y ago
In Switzerland, breathalizers may be used to justify pulling people out during traffic controls, but only a blood test is valid proof of too much blood alcohol before court. Is that different in the US? After all, even ripe fruit can result in a breath test indicating too much alcohol.
- skc 9y ago
  There are now breathalyzers that are near enough as accurate as blood tests that are admissible in court these days. But they are huge machines kept at the police station after you've been hauled in after failing the normal road side breathalyzer test.
  - alkonaut 9y ago
    And that’s the type of machine being questioned in the article, not the roadside ones? Should be clearer - and if those bulky machines are replaced with blood tests (assuming they are much more reliable) I don’t see the problem. Having doubt in the test used to bring someone to a second test is fine. The second test is used for conviction so there can’t be any doubt.
  - MertsA 9y ago
    >There are now breathalyzers that are near enough as accurate as blood tests But in the general case this is quite simply not possible. It might be very accurate in the controlled case of a subject who hasn't consumed anything in the past hour but these breathalyzers are not being used in a nice controlled environment. The concentration of alcohol in a breath can vary wildly compared to the concentration in the blood. If someone used e.g. mouthwash a few minutes before being tested it will indicate a high BAC even if it's actually zero. Unless the police are going to start forcing people to brush their teeth, clean their tongue, and use some form of non alcoholic mouthwash before testing you can't come close to the sort of accuracy that an actual blood test would give. In real world conditions there are too many situations where the concentration of alcohol in your breath is substantially different than the concentration of alcohol in your blood.
APCarr 9y ago
I use a cheap breath tester to see if I'm in ketosis when losing weight (burning fat creates ketones, which trigger breath tests). Jus' sayin'.
- raarts 9y ago
  What's the precision of that device?
- VectorLock 9y ago
  How does that compare to using test strips?
- 2RTZZSro 9y ago
  You should be skeptical of the output of a ketone measurement device. You need to measure blood concentration of beta-hydroxybutyrate to accurately determine your ketosis situation.
rascul 9y ago
The biggest flaw is that it doesn't actually measure drunkenness or impairment.
- pc86 9y ago
  If you're going to be arresting people for DUI, you need an objective measure of impairment. Whether or not someone can walk in a straight line or say the middle third of the alphabet should be plenty for probably cause but not enough to arrest someone.
  - maxerickson 9y ago
    BAC isn't an objective measure of impairment, it's a measure of BAC. But short of an actual objective test, arresting people for driving after consuming alcohol is plenty reasonable to me.
    - dragonwriter 9y ago
      > BAC isn't an objective measure of impairment It is, it's just not a precise one. (Yes, it's an indirect proxy measure, but so are all measures on some levem.)
    - pc86 9y ago
      So you want the legal limit to drive to be 0.0? Or something else? How long after I have half a glass of wine with dinner do I need to wait before I can drive?
      - maxerickson 9y ago
        No, I'm just saying it isn't really an objective measure of impairment, but that's fine, people over some limit have clearly been drinking enough that they still shouldn't be allowed to drive.
- alkonaut 9y ago
  I’d rather have an objective measurement of blood alcohol than a subjective measurement of drunkenness. People can’t judge their own capability or drunkenness so even if you ace a reaction/driving/balance/whatever-test with a high blood alcohol level, there is nothing to say that you could have judged that ability. That’s why the law isn’t against driving drunk or impaired it’s a law against driving with alcohol in your blood.
thaumaturgy 9y ago
It doesn't look like this is an error that will cause a totally sober person to fail a breathalyzer test. If you're worried about the accuracy of the machine, you can also submit to a blood test: https://duilawyerlosangeles.com/dui-lawyer-advice-breathalyzer-vs-blood-test/ https://duilawyerlosangeles.com/dui-lawyer-advice-breathalyz... This is one issue where I'm firmly on the side of the police until there's evidence that faulty breathalyzers are putting totally innocent people in jail. If you choose to get into the driver's seat of a car, you should not be anywhere near the legal BAC limit. By the time an officer asks you to submit to a BAC test, they've already observed enough behavior to make them believe that you may be a danger to others. Plan ahead so that you don't have to worry about leaving your car somewhere. Call an Uber or a Lyft. Get a friend to drive you home. Moderate your drinking. Take some time, go for a long walk. On popular holidays in many places, you can even call AAA for a free ride home, even if you're not a member. Just please don't drive home on the hope that a defense lawyer can argue on your behalf that breathalyzers aren't reliable.
- Clubber 9y ago
  When someone blows a 0.08 when it really is a 0.07, that would be putting an innocent person in jail.
  - simion314 9y ago
    Don't you have the right to ask for blood tests where you live?
    - Clubber 9y ago
      I don't know, but I don't like needles, so I probably wouldn't. That's not really the point though.
    - DennisP 9y ago
      Getting a blood test means either going to the police station, or letting a cop stick a needle in you on the side of the road. We should do whatever we can do avoid making innocent people do either one.
stochastic_monk 9y ago
This is a feature, not a bug. In fact, many jurisdictions have requirements that, above a breathalyzer-reported BAC threshold, different minimum mandatory punishments are levied. Sure, a sober person won't get a result that's above the legal limit most of the time, but someone who's done some drinking and is within appropriate parameters is often labeled as DUI, and could potentially register as above this higher, mandatory-jailtime, mandatory-felony situation. I've known of cases where the breathalyzer in question has been shown to be broken and decommissioned, yet the people whose numbers were so wildly inflated that they couldn't possibly be accurate have still been convicted using these numbers. In one case in particular, the judge ruled that the evidence on the unreliability of the machines in general (and this machine in particular) was not admissible for court. It's about punishment, not deterrence.
DennisP 9y ago
The police department says they "approved the instrument that best fit our business needs." It's a bit disturbing that they think of themselves as a business, especially since arguably their business need is to get as many convictions as possible.
instaheat 9y ago
I got a DWI in 2009, pre Uber/Lyft. I don't excuse my actions and I got what I deserved. That being said, I would never consent to a breathalyzer or field sobriety test today sober or not. I see no issue with flexing our rights and really get tired of the "just comply" narrative.
- frandroid 8y ago
  As opposed to pre taxis?
dsfyu404ed 9y ago
This is news to exactly nobody who ever read the manufacturer specs of the sensors used in devices that detect alcohol for law enforcement. They're running industrial process control sensors at the limits of their range and in widely changing environment. It should come as no surprise that they're hard to calibrate accurately and likewise deliver variable results in a lot of cases In a factory environment equipment doesn't get calibrated in a 70deg car and used in 20deg winter air to measure 90deg human breath. In law enforcement that's exactly what happens. Ankle bracelets are even worse. The fact of the matter is that most hardware/software solutions sold to law enforcement are only a small step above the scam bomb-detectors that got sold to the Iraq government (Google it if you're unfamiliar with the story). If NASA were writing the calibration code, the results weren't being interpreted by laymen and their interpretation wasn't being used to destroy lives I'd feel differently.
arbuge 9y ago
This is not really news. For example in Texas, DWI lawyers run a lucrative racket combating breathalyzer test results using the known flaws in the machine and its application. Blood tests are considered more definitive and harder to defend against.
- pavel_lishin 9y ago
  Why is it a racket?
sli 9y ago
There is at least one model where, if the officer covers the outlet tube, the reading doubles extremely reliably. I saw this tested in a short documentary some years back. If you're going to get breathalyzed, will you notice if the officer is doing something shady? Could you even know, without knowledge of the various machines? I'm also quite miffed that a cop can give you a DUI even if your reported (by the machine) BAC is under the legal limit, 0.00 included.
kkielhofner 9y ago
It should be know that in many jurisdictions (at least within the US) the officer's belief that you're impaired is usually enough for arrest - regardless of the outcome of any field sobriety tests or machine results. On one hand I understand this approach due to the dizzying array of factors that cause impaired driving - from alcohol to prescription drugs to designer drugs that may not have definitive tests available. Seeing as sleep deprived drivers often perform as poorly as impaired drivers on various tests that should be included as well. On the other, this is still a situation where an officer's opinion with no supporting evidence (or conflicting evidence) can lead to arrest. Sure, you may "win" in front of a judge eventually but this is after you get handcuffed, spend the night in jail, have an arrest on your record, etc. Not to mention having your mugshot posted online by various unscrupulous sites running an extortion racket (demanding payment to remove). You'll soon discover that to many people simply being arrested = guilty. In my case my "win" came 14 months later when the judge watched the dashcam footage, saw that my driving, speech, behavior, etc clearly wasn't impaired and threw the case out. Total time in court was less than 20 minutes. Interestingly we watched the dash cam footage after the officer testified. At one point my attorney asked why the officer thought I was impaired. He responded with "I'm Irish Catholic and I know what drunk people look like". The entire courtroom (myself included) laughed.
- craftyguy 9y ago
  > He responded with "I'm Irish Catholic and I know what drunk people look like". Perhaps the officer was impaired.
lisper 9y ago
I drink and drive all the time, which is to say, I will drive to a restaurant, enjoy dinner and drinks, wait, and then drive home. In order to be sure that I've waited long enough to be safe, I bought a BACtrack S35 breathalyzer to keep in my car. In many, many years of testing myself, I have never seen a reading above 0.03, at which point I feel pretty impaired. If I'm over 0.02, I don't drive. I don't think I could stay conscious long enough to get myself up to the 0.08 legal limit. All of which makes me wonder: can I trust this gadget to be properly calibrated? And how would I find out? The only way I can think of is to approach a police officer while drunk and ask them to breahalyze me so I can compare readings. Somehow, the opportunity to do that has never arisen. It seems to me like a no-brainer that any establishment that serves alcohol ought to be required by law to have a properly calibrated breathalyzer on the premises for its customers to use. But of course this won't happen because the truth is we don't really want to know. We have drunk-driving theatre just like we have security theatre, and both seem to be a stable equilibrium. Alas.
- supergeek133 9y ago
  BACTrac actually recommends you send it to them on a regular basis for calibration
  - lisper 9y ago
    Sure. But the results I get today are consistent with the ones I got when the unit was brand new. In fact, it's so consistent I can predict with very high accuracy what my reading will be just based on how much I've had to drink and how I feel. So if the unit is inaccurate now, it was inaccurate when it was new. Also, we have two units, one in my car, one in my wife's car. I've tested myself back-to-back with both units (at home) several times and the readings are always consistent.
    - supergeek133 9y ago
      Yeah fair (and that's awesome, I think mine went out of calibration after like a year)... but like I said in another comment. If devices are inconsistent it doesn't really matter.
kevin_thibedeau 9y ago
Why would it even be possible to disable sensors critical to getting a credible estimate of blood alcohol? It all sounds like a convenient way to boost revenue with false positives while hiding behind the techno-wizardry.
DrScump 9y ago
Years ago, on "L.A. Law", a story arc had one of the lawyers stopped for weaving. His partner advised him, "breath or unine -- not blood!". This was in CA, which gives the driver his/her choice of the three methods. Are there cases where blood disfavors the suspect?

133 points by uptown 9y ago

Remind me again why a device paid for with public funds and used to carry out essential public functions of the government should be anything but open source.

sigstoat 9y ago
the government buys some of very nearly everything and uses them to carry out essential public functions. you've got to have a better criteria than that.
- logfromblammo 9y ago
  The defense in a criminal case has the right to examine witnesses that presented evidence against them. When the witness is a machine, such an examination must necessarily include inspection of the operating protocols, technical specifications, calibration records, and source code. Forcing the defense to ask for it in discovery for every single case seems somewhat counterproductive. If your code is being used to put people in prison, you don't get to keep your trade secrets privilege.
  - alistairSH 9y ago
    It is counterproductive. It's also a feature of the system. At best (for the accused), thousands of dollars get spend on defense, pumping money into pockets of lawyers. At worst, the accused can't afford this level of defense and the DA gets another notch in their belt.
jpdb 9y ago
Because the software/IP isn't owned by the government. I'd personally rather the US government pick the best solution, not the most open source one. I would hope the best solution is open source, but the gov't shouldn't be forced to sacrifice quality. However, I can agree that any Software/IP developed via public funds should definitely be open source.
- DennisP 9y ago
  Define "best." My definition would be something that's not only accurate in most conditions, but lets the accused mount a meaningful defense. Comprehensive testing by an independent lab gets us partway, if all the results are available to the defense, but it's better if we can both do black box testing and examine the code.
- thatcat 9y ago
  How should the public verify the government has chosen the best solution if the design of the solution isn't readily available? Depending on your perspective and definition of best, faulty designs that give more favorable results could deliberately be chosen to increase revenue / crime stats.
- jononor 9y ago
  Trustworthyness is (or maybe should) be an criteria for things being used to provide data for legal matters. Being able to independently verify the device is critical for this, and open-source makes this easier.
- craftyguy 9y ago
  > I'd personally rather the US government pick the best solution, not the most open source one. I'd personally rather the US government consider trustworthiness, which is only afforded in open source projects, to be an important criteria for "best solution."

dbrgn 9y ago

In Switzerland, breathalizers may be used to justify pulling people out during traffic controls, but only a blood test is valid proof of too much blood alcohol before court. Is that different in the US? After all, even ripe fruit can result in a breath test indicating too much alcohol.

skc 9y ago
There are now breathalyzers that are near enough as accurate as blood tests that are admissible in court these days. But they are huge machines kept at the police station after you've been hauled in after failing the normal road side breathalyzer test.
- alkonaut 9y ago
  And that’s the type of machine being questioned in the article, not the roadside ones? Should be clearer - and if those bulky machines are replaced with blood tests (assuming they are much more reliable) I don’t see the problem. Having doubt in the test used to bring someone to a second test is fine. The second test is used for conviction so there can’t be any doubt.
- MertsA 9y ago
  >There are now breathalyzers that are near enough as accurate as blood tests But in the general case this is quite simply not possible. It might be very accurate in the controlled case of a subject who hasn't consumed anything in the past hour but these breathalyzers are not being used in a nice controlled environment. The concentration of alcohol in a breath can vary wildly compared to the concentration in the blood. If someone used e.g. mouthwash a few minutes before being tested it will indicate a high BAC even if it's actually zero. Unless the police are going to start forcing people to brush their teeth, clean their tongue, and use some form of non alcoholic mouthwash before testing you can't come close to the sort of accuracy that an actual blood test would give. In real world conditions there are too many situations where the concentration of alcohol in your breath is substantially different than the concentration of alcohol in your blood.

APCarr 9y ago

I use a cheap breath tester to see if I'm in ketosis when losing weight (burning fat creates ketones, which trigger breath tests). Jus' sayin'.

raarts 9y ago
What's the precision of that device?
VectorLock 9y ago
How does that compare to using test strips?
2RTZZSro 9y ago
You should be skeptical of the output of a ketone measurement device. You need to measure blood concentration of beta-hydroxybutyrate to accurately determine your ketosis situation.

rascul 9y ago

The biggest flaw is that it doesn't actually measure drunkenness or impairment.

pc86 9y ago
If you're going to be arresting people for DUI, you need an objective measure of impairment. Whether or not someone can walk in a straight line or say the middle third of the alphabet should be plenty for probably cause but not enough to arrest someone.
- maxerickson 9y ago
  BAC isn't an objective measure of impairment, it's a measure of BAC. But short of an actual objective test, arresting people for driving after consuming alcohol is plenty reasonable to me.
  - dragonwriter 9y ago
    > BAC isn't an objective measure of impairment It is, it's just not a precise one. (Yes, it's an indirect proxy measure, but so are all measures on some levem.)
  - pc86 9y ago
    So you want the legal limit to drive to be 0.0? Or something else? How long after I have half a glass of wine with dinner do I need to wait before I can drive?
    - maxerickson 9y ago
      No, I'm just saying it isn't really an objective measure of impairment, but that's fine, people over some limit have clearly been drinking enough that they still shouldn't be allowed to drive.
alkonaut 9y ago
I’d rather have an objective measurement of blood alcohol than a subjective measurement of drunkenness. People can’t judge their own capability or drunkenness so even if you ace a reaction/driving/balance/whatever-test with a high blood alcohol level, there is nothing to say that you could have judged that ability. That’s why the law isn’t against driving drunk or impaired it’s a law against driving with alcohol in your blood.

thaumaturgy 9y ago

It doesn't look like this is an error that will cause a totally sober person to fail a breathalyzer test. If you're worried about the accuracy of the machine, you can also submit to a blood test: https://duilawyerlosangeles.com/dui-lawyer-advice-breathalyzer-vs-blood-test/ https://duilawyerlosangeles.com/dui-lawyer-advice-breathalyz... This is one issue where I'm firmly on the side of the police until there's evidence that faulty breathalyzers are putting totally innocent people in jail. If you choose to get into the driver's seat of a car, you should not be anywhere near the legal BAC limit. By the time an officer asks you to submit to a BAC test, they've already observed enough behavior to make them believe that you may be a danger to others. Plan ahead so that you don't have to worry about leaving your car somewhere. Call an Uber or a Lyft. Get a friend to drive you home. Moderate your drinking. Take some time, go for a long walk. On popular holidays in many places, you can even call AAA for a free ride home, even if you're not a member. Just please don't drive home on the hope that a defense lawyer can argue on your behalf that breathalyzers aren't reliable.

Clubber 9y ago
When someone blows a 0.08 when it really is a 0.07, that would be putting an innocent person in jail.
- simion314 9y ago
  Don't you have the right to ask for blood tests where you live?
  - Clubber 9y ago
    I don't know, but I don't like needles, so I probably wouldn't. That's not really the point though.
  - DennisP 9y ago
    Getting a blood test means either going to the police station, or letting a cop stick a needle in you on the side of the road. We should do whatever we can do avoid making innocent people do either one.

stochastic_monk 9y ago

This is a feature, not a bug. In fact, many jurisdictions have requirements that, above a breathalyzer-reported BAC threshold, different minimum mandatory punishments are levied. Sure, a sober person won't get a result that's above the legal limit most of the time, but someone who's done some drinking and is within appropriate parameters is often labeled as DUI, and could potentially register as above this higher, mandatory-jailtime, mandatory-felony situation. I've known of cases where the breathalyzer in question has been shown to be broken and decommissioned, yet the people whose numbers were so wildly inflated that they couldn't possibly be accurate have still been convicted using these numbers. In one case in particular, the judge ruled that the evidence on the unreliability of the machines in general (and this machine in particular) was not admissible for court. It's about punishment, not deterrence.

DennisP 9y ago

The police department says they "approved the instrument that best fit our business needs." It's a bit disturbing that they think of themselves as a business, especially since arguably their business need is to get as many convictions as possible.

instaheat 9y ago

I got a DWI in 2009, pre Uber/Lyft. I don't excuse my actions and I got what I deserved. That being said, I would never consent to a breathalyzer or field sobriety test today sober or not. I see no issue with flexing our rights and really get tired of the "just comply" narrative.

frandroid 8y ago
As opposed to pre taxis?

dsfyu404ed 9y ago

This is news to exactly nobody who ever read the manufacturer specs of the sensors used in devices that detect alcohol for law enforcement. They're running industrial process control sensors at the limits of their range and in widely changing environment. It should come as no surprise that they're hard to calibrate accurately and likewise deliver variable results in a lot of cases In a factory environment equipment doesn't get calibrated in a 70deg car and used in 20deg winter air to measure 90deg human breath. In law enforcement that's exactly what happens. Ankle bracelets are even worse. The fact of the matter is that most hardware/software solutions sold to law enforcement are only a small step above the scam bomb-detectors that got sold to the Iraq government (Google it if you're unfamiliar with the story). If NASA were writing the calibration code, the results weren't being interpreted by laymen and their interpretation wasn't being used to destroy lives I'd feel differently.

arbuge 9y ago

This is not really news. For example in Texas, DWI lawyers run a lucrative racket combating breathalyzer test results using the known flaws in the machine and its application. Blood tests are considered more definitive and harder to defend against.

pavel_lishin 9y ago
Why is it a racket?

sli 9y ago

There is at least one model where, if the officer covers the outlet tube, the reading doubles extremely reliably. I saw this tested in a short documentary some years back. If you're going to get breathalyzed, will you notice if the officer is doing something shady? Could you even know, without knowledge of the various machines? I'm also quite miffed that a cop can give you a DUI even if your reported (by the machine) BAC is under the legal limit, 0.00 included.

kkielhofner 9y ago

It should be know that in many jurisdictions (at least within the US) the officer's belief that you're impaired is usually enough for arrest - regardless of the outcome of any field sobriety tests or machine results. On one hand I understand this approach due to the dizzying array of factors that cause impaired driving - from alcohol to prescription drugs to designer drugs that may not have definitive tests available. Seeing as sleep deprived drivers often perform as poorly as impaired drivers on various tests that should be included as well. On the other, this is still a situation where an officer's opinion with no supporting evidence (or conflicting evidence) can lead to arrest. Sure, you may "win" in front of a judge eventually but this is after you get handcuffed, spend the night in jail, have an arrest on your record, etc. Not to mention having your mugshot posted online by various unscrupulous sites running an extortion racket (demanding payment to remove). You'll soon discover that to many people simply being arrested = guilty. In my case my "win" came 14 months later when the judge watched the dashcam footage, saw that my driving, speech, behavior, etc clearly wasn't impaired and threw the case out. Total time in court was less than 20 minutes. Interestingly we watched the dash cam footage after the officer testified. At one point my attorney asked why the officer thought I was impaired. He responded with "I'm Irish Catholic and I know what drunk people look like". The entire courtroom (myself included) laughed.

craftyguy 9y ago
> He responded with "I'm Irish Catholic and I know what drunk people look like". Perhaps the officer was impaired.

lisper 9y ago

I drink and drive all the time, which is to say, I will drive to a restaurant, enjoy dinner and drinks, wait, and then drive home. In order to be sure that I've waited long enough to be safe, I bought a BACtrack S35 breathalyzer to keep in my car. In many, many years of testing myself, I have never seen a reading above 0.03, at which point I feel pretty impaired. If I'm over 0.02, I don't drive. I don't think I could stay conscious long enough to get myself up to the 0.08 legal limit. All of which makes me wonder: can I trust this gadget to be properly calibrated? And how would I find out? The only way I can think of is to approach a police officer while drunk and ask them to breahalyze me so I can compare readings. Somehow, the opportunity to do that has never arisen. It seems to me like a no-brainer that any establishment that serves alcohol ought to be required by law to have a properly calibrated breathalyzer on the premises for its customers to use. But of course this won't happen because the truth is we don't really want to know. We have drunk-driving theatre just like we have security theatre, and both seem to be a stable equilibrium. Alas.

supergeek133 9y ago
BACTrac actually recommends you send it to them on a regular basis for calibration
- lisper 9y ago
  Sure. But the results I get today are consistent with the ones I got when the unit was brand new. In fact, it's so consistent I can predict with very high accuracy what my reading will be just based on how much I've had to drink and how I feel. So if the unit is inaccurate now, it was inaccurate when it was new. Also, we have two units, one in my car, one in my wife's car. I've tested myself back-to-back with both units (at home) several times and the readings are always consistent.
  - supergeek133 9y ago
    Yeah fair (and that's awesome, I think mine went out of calibration after like a year)... but like I said in another comment. If devices are inconsistent it doesn't really matter.

kevin_thibedeau 9y ago

Why would it even be possible to disable sensors critical to getting a credible estimate of blood alcohol? It all sounds like a convenient way to boost revenue with false positives while hiding behind the techno-wizardry.

DrScump 9y ago

Years ago, on "L.A. Law", a story arc had one of the lawyers stopped for weaving. His partner advised him, "breath or unine -- not blood!". This was in CA, which gives the driver his/her choice of the three methods. Are there cases where blood disfavors the suspect?