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Launch HN: SannTek (YC S19) – Breathalyzer for Cannabis
224 points by Noah_SannTek on Aug 16, 2019 | hide | past | favorite | 394 comments
Hey HN, I'm Noah, co-founder of SannTek (https://www.sannteklabs.com). We're building a breathalyzer for cannabis.

I bet some of you have had the same idea cross your mind that we had: "If we have a breathalyzer for alcohol, why don't we have a breathalyzer for cannabis?" We're nanotechnology engineering alumni from the University of Waterloo. Two factors led into us deciding to pursue this idea: 1. Cannabis was being legalized across Canada and police were completely ill-prepared, so we saw an opportunity to help; 2. the science required to make this device exist was particularly interesting.

Alcohol breathalyzers are fundamentally a fuel cell where the alcohol in your breath sample is oxidized, which then produces an electrical current that the device then translates to BAC. For alcohol, this works because of Henry's Law, which says that at any given temperature the ratio between the concentration of alcohol in the blood and that in the alveolar air in the lungs is constant.

Cannabis is a very different beast. Not only is it a non-volatile, fat-soluble molecule, but the mechanism in which THC (the psychoactive component of cannabis) appears in your breath isn't super straight forward. Also, it is present in much lower concentrations in the breath compared to alcohol. Whereas a blood alcohol concentration of 0.08% (the legal limit in most states) might result in a concentration of 208 ppm of ethanol in the breath, a similarly impairing dose of cannabis results in 0.00001 ppm of the drug in breath.

Detecting such a low concentration is difficult, and as a result, cannabis drug use has been detected in a variety of sub-optimal ways. The state of the art is a blood draw, followed by detection of THC at a toxicology laboratory using liquid chromatography-mass spectrometry. While accurate and well-validated, this approach has several problems. First of all, since THC is fat-soluble it remains in a person's body much longer than alcohol, especially if that person is a frequent user. Frequent users have been known to have detectable THC in their blood one week after beginning abstinence. These people are clearly not impaired all week but could be arrested and charged with a DUI based on many states laws across the US. Interestingly, police have the opposite problem with infrequent users. For most people, the concentration of THC in their system will decay quickly post-consumption. It takes around 2 hours (at best) for a police officer to get a blood draw from a suspect. At this point, many people will no longer have detectable THC in their system. Our device solves both these problems for police. Our breathalyzer uses an ultra-sensitive immunosensor to detect the minute concentration of THC in breath. Breath is the better medium for cannabis testing for several reasons. First of all, THC concentration in breath for both frequent users and infrequent users decays below detectable levels within 3-4 hours post-consumption and we have never detected THC in the baseline for any of our subjects. So our device does not incorrectly identify frequent users as impaired as blood testing can. Secondly, the breath tests can be administered quickly roadside, eliminating the risk of concentration decay seen with blood draws.

Our device comes with a reusable analyzer and a single-use disposable cartridge. It costs us $2 to make a cartridge, and police are willing to pay $20 per test. An individual will breathe into the mouthpiece, and our filter system will collect exhaled breath particles (specifically non-VOCs). Currently, we manually "extract" the THC off of the filter into a solvent liquid, but in the future, this will be automated using novel microfluidics. The solvent, with the captured THC, is then transferred to the surface of the sensor- which is an electrochemical immunoassay. When the THC is there, the output signal is different than when the THC is not there (happy to dive further into this in the comments if people are interested).

We haven't had enough resources to run any formal trials yet to publish data, but that is changing this year. We've hired a contract research organization, (shout out Curebase), to help us run our very first clinical trial with blood draws. We're going to be looking at the correlation between breath and blood concentrations, at various time intervals after consumption, to validate (or invalidate!) our preliminary in house data.

Selling to the police is notoriously difficult, but we're imagining a world where there are one of our devices in every police car in North America. This weekend we exhibited at the IACP DAID and the response from the attendees was great! We have over 30 police departments across North America that have expressed interest in purchasing the device and that number is increasing every day.

We're excited to hear all your questions and feedback! I encourage any questions you may have for us :)

Sounds like it’s well-intentioned, but I’m afraid that given the incentives of all parties involved here, and the complexity of the technology, there will be a lot of false positives.

It’s obvious that the police will want a device that produces more convictions, no point in disputing that.

I’m wondering if you can elaborate on what incentives your company has to produce accurate devices, against your customer’s unstated preferences. What’s keeping you in check? Are you worried about class action lawsuits from victims of false positives, if it were independently proven that your device is overly sensitive?

You raise a good point. Interestingly, your comments run contrary to what a lot of law enforcement officers have said to us.

In general, the police are hyper vigilant about buying only devices that are independently validated to be very accurate. Every conversation we have had has eventually lead to "is it NHTSA approved?". The reason for this need for third party validation is that the police are incredibly court room sensitive. If there is any chance a defense attorney would be able to pull out a study showing low specificity or sensitivity for a device, the police will simply not buy it. Third party validation gives them that guarantee.

You are right that the police want more convictions (or less time consuming convictions), but the way they do that is by having very accurate devices that are defensible in court, not inaccurate devices that risk cases being thrown out. That is why making sure our device has low false positive is very important.

I admire what you're doing, and hope you can adhere to scientific integrity while developing and selling your product, but that simply isn't true. At least in Washington state. A few years ago Washington State purchased a whole bunch of Draeger 9510 (alcohol breathalyzer) units without ever having tested them. After two years of sitting unused, the warranties were going to expire and they finally got around to testing them, and purchasing extended warranties at that point. However their initial tests failed multiple accuracy tests to the point that the state's lab halted testing, since it was so off. A few months later Draeger patched the firmware and OS application (the breath/alcohol measurement firmware being written by a single contractor in Texas, and versioned as 0.7) and while testing looked better, it still wasn't accurate and they just pushed it out the door for deployment...they had already bought them, after all. I'll link the records below...they didn't even have the correct versions of the software and firmware accounted for and signed off, which led to other problems (and Draegar has had other problems of accuracy in other court cases, such as Florida, but that's a side tangent).

My point is, a lot of state governments (at least in the US) spend money first and verify later, and 'verify' can be a damnably loose term. Loose enough to violate WAC 448-15-020 (in Washington state's case) which requires a 'reasonable degree of scientific accuracy'.

EDIT: Apparently the original link (below) is no longer available in WSP's records, which is interesting. You can view the document via archive.org, here


original (defunct) http://www.wsp.wa.gov/breathtest/docs/webdms/Draeger/Valid_D...

Thanks for the info. Definitely something we have not run into or considered yet. I guess we just naively assumed that all police precincts were as scrupulous as those we talked to :(.

There is some stuff we can do, however. For instance, we can directly build the QC schedule into the device so it does not work unless you get it calibrated. We can also have QC cartridges that have a barcode that the device reads to make sure you actually ran a calibration check properly and the device passed.

We were so focused on internal methods for making the device accurate, but maybe we should put some thought into how we can make sure the police use it properly.

>I guess we just naively assumed that all police precincts were as scrupulous as those we talked to :(.

Bless your heart.

Really, if you're producing something that is reliably accurate, I would expect that would be all anyone would expect, along with proper training, verified updates, and audited software/firmware, etc. In the case I cited above it was more an issue with the lack of accuracy of the product, and sloppy follow through from the vendor, with money and political pressure thrown at the problem - something which the police departments themselves likely have less influence on anyway.

If your product is at all worthwhile, it will constantly be tossed back and forth between lawyers, trying to uphold or disprove its validity. ("Well here's an independent study done on how arresting officers with shaky hands get inconsistent results when administering the SannTek Cannibus test" et al et al ad nauseum) While yes, this is a problem in any society that applies capitalism principles to the practice of law.... I don't think there's necessarily a better system, sadly. Don't feel responsible to fix it all yourself. Anyway, pursue the technology as well as possible, by all means work in as many checks and balances as possible for correct use, and constant calibration, BUT ALSO talk and document openly during your design phase and testing the ideology you develop to govern false positives versus false negatives. This is an extremely engaging technology ethics discussion. If you drive the error to be false negatives, at a rate of 5%, will you not be able to sell it, because your customer is most interested in an effective tool? What is the societal benefit of getting this device to be accepted and used by the police? If you can achieve FN=4% is it worth it, or is the societal benefit actually much higher, possibly at FN =20%. Can you just run the test 5 times in a row, or with 2 stand alone devices to reach the dependability rate you desire? If you drive the error to be false positives, at a rate of 1%, can you sleep at night with the lives your product will effect, or do you need a fall back like your device determining with 100% accuracy that cannibus is present in someone's system (just not a definitive, exact amount), PLUS a statement from an arresting officer stating erratic or dangerous driving or behavior in conjunction with your device's input. I'm very excited about what you're doing. I didn't know (still not yet convinced) that the science is solvent, but I've been asking about this device for years.

Everyone says they are ethical including the unethical I'm not sure how you possibly took this at face value.


reading HN as a woman is an exercise in managing fury

My apologies if I have caused offense. I have angered you here and this wasn't my intention.

One thing I will say is that the prefixes I gave are in general use as descriptive epithets by both men and women across much of the English speaking world, along with many others decribing the male genitalia, with much greater frequency than you will find on here. Personally, I'm with Alice Fraser on this one - https://www.youtube.com/watch?v=gioul9PW9B0 - but will cheerfully adapt the taxonomy in future, if I can find better words to use for the prefixes. Any ideas?

Why not just say what you mean? The prefixes you used are incomprehensible without the parentheticals following them ("(deliberate misuse)" etc.), so why not just use those?

I'm not convinced it breaks down into three clean categories anyway.

>The prefixes you used are incomprehensible without the parentheticals following them

I disagree. In the taxonomy of these things, being a twat is more impulsive misbehaviour, while being a cunt involves malicious aforethought and intent. There is a fairly clear meaning from that general usage.

>I'm not convinced it breaks down into three clean categories anyway.

I agree, but I didn't make it up and people tend to use the rule of three for stuff like this. I suppose a category of dickproof could be added between foolproof and twatproof, but I think it already has a lot of overlap with foolproof.

I think your "general usage" is actually fairly specific to particular places and people. Without the explanations, I wouldn't have gleaned the meanings you're assigning (I'm a native English speaker from NZ). It seems pointlessly obfuscated and offensive to me.

Thought I'd go find out if I was being particularly insensitive or if people were clutching their pearls a bit tightly. Couldn't find many examples, but here they are in the wild and not causing any noticable problems.

Firstly, twatproof, from reply #14 in the Festool owner's group to a question about dovetails:

>"I just had a go with the Festool jig and it's the most twatproof solution I've ever seen."


and secondly, cuntproof, on twitter, with someone called Wiryjack describing the term to the award winning writer and naturalist Helen Macdonald:

>"A mechanic I used to know described things as 'cuntproof', which I took to mean foolproof but extra robust to deter the malicious as well as the stupid."


I may note that Helen Macdonald apparently considers cuntproof to be an excellent term, well worth adding to her vocabulary.

This seems like a very strange idea to triple down on. Take or leave the feedback, but I'm not sure you are helped by trying to debate the relative merit of these terms.

FWIW, as a native English speaker I also found your post both needlessly offensive and equally inscrutable.

Fair, I know I am digging a bit of a hole. Partly I am interested in the semantics and partly it is the first time that I have encountered people being particularly pissed off by the concept. Most people I have described it to in the past seemed to find it either funny or useful, so I was surprised by the pushback. I mean, you can say fuck on here and nobody gives a damn, hell, you can name an entire language brainfuck and everybody claps, but this use of language is way out and I am interested in why. I figured that if I dug a little deeper on an already flagged thread, it would not cause any particular harm. Anyone discussing this with me from then on in, is doing so after delving into something clearly marked with 'here be dragons'.

> In general, the police are hyper vigilant about buying only devices that are independently validated to be very accurate.

How do you reconcile that with the reality of the NIK tests which are notoriously unreliable and ubiquitous among police departments?

Like the lie detector?

> It’s obvious that the police will want a device that produces more convictions, no point in disputing that.

Is that obvious? If this were as overwhelming an incentive as you say, we wouldn't have accurate breathalyzers for alcohol. But we do, and it's simple to see why. 1) Cops aren't the only customers; medical establishments, individuals, and workplaces also have a legitimate interest in measuring impairment. 2) Tech like this doesn't remain novel forever, it can be checked for accuracy, and if you made a device that exaggerated impairment your reputation would tank, your company name would become a political hot potato, and your sales would never materialize. 3) There is definitely a point in disputing the idea that cops are indiscriminate gangsters roaming the streets trying to lock up any citizen they don't like the look of. Police have their personal and institutional biases, but by and large, most are interested in tools that allow them to safely and fairly administrate the rule of law. Police don't have much career or institutional incentive to arrest someone for a DUI at a traffic stop or not—they just stop bad drivers and check. It's prosecutors who are trying to rack up conviction numbers as a matter of career advancement and political viability. But even that gets checked: their work will be subject to an adversarial legal system, at which point any evidence that the device doesn't work would come out in court and tank their conviction rate.

So... where do you see perverse incentives here, again?

Do we have accurate breathalyzers for alcohol? AFAIK, the manufacturers aggressively resist requirements to publish their source code or calibrations for testing. Also, AIUI, the devices require recalibration for accuracy, and it's not clear that police stations perform such maintenance.

No idea how rampant this is, every system will have flaws. But I question whether we can use the alcohol breathalyzer example without acknowledging there are significant unanswered questions w/r/t accuracy.

A friend of a friend works at a facility which calibrates + certifies police breathalysers and by his account below 0,015% BAC the result is garbage, so some countries choose to set the limit at 0,02% which is enough for the devices to indicate properly most of the time.

If breathalyzers were inaccurate, uncalibrated, or unmaintained it would be trivial to get any conviction relying on their measurements thrown out.

Only if you're allowed to test the devices in question, and the courts believe your experts over the manufacturers.

This doesn't prove my point, but manufacturers do aggressively fight against researchers identifying flaws in their products. Given the high stakes (+ the fact this isn't a security issue, really), it seems like a major smell to me.

There are reports out there of people convicted, who are blocked from examining the devices used as the primary piece of evidence against them.

Also, after years of effort to discredit breathalyzer results, convictions ARE being overturned regularly.

NJ overturns > 27k convictions because of breathalyzer issues - https://www.nytimes.com/2018/11/13/nyregion/nj-dwi-convictio...

MS judge suspends admission of breathalyzer evidence -- https://www.bostonherald.com/2019/01/10/breathalyzers-tempor...

More relevant info - https://www.zdnet.com/article/draeger-breathalyzer-breath-te...

Nothing about the court system is trivial.

What makes you say that?

The National Highway Traffic Safety Administration report to Congress [0] seems pretty clear in terms of the art of the science and the impairment observed from national data.

I would avoid incarceration of anyone from a test like this without significant and clear data that there is an actual problem we need to resolve. There are plenty of well proven driving problems we could focus on correcting.

[0] https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/documents/81...

> What’s keeping you in check?

It's going to be fairly easy to test this. You take one group of people who haven't smoked in the last few hours and you test them. Make sure it doesn't go off. You take another group who have smoked (I'm sure plenty of college students would be happy to sign up for this trial) and you test them, make sure it does go off. It's pretty simple. It's a machine with an empirical number, so you don't even have to do this double blind.

And if it doesn't give good results? It won't hold up in court. Every lawyer defending someone with a positive result (whether false positive or true positive) will argue that the device isn't accurate and the case gets tossed (or even the ability to use these as evidence). If it doesn't hold up in court, police really won't have much incentive to use these anyway.

Even alcohol breathalyzers are regularly miscalibrated or defective and found to produce false positives. Legal pressure from manufacturers keeps this quiet.


That is why many states follow a positive breathalyzer test with a blood test. In my state, you can refuse them both, but you lose your license temporarily for doing so. I think that's fair. I understand some are skeptical about giving blood to the police, but if you can't prove you're not drunk or high after a positive reading on a less accurate device, then you aren't allowed on the road. The risk is too great for everyone else.

In Texas, you receive a mandatory suspension for refusing just a breathalyzer, even if you are found to not be over the legal limit, or are never convicted of a DWI. Blood tests are then often obtained via warrant (and it's typical to have a judge "on call" to sign and fax those orders on demand)

That's utterly disgusting that the state can invade your body and take blood out with a warrant.

I personally think it's utterly disgusting that people are allowed to operate what are essentially giant weapons in public with extremely minimal testing or training, and with minimal limits on alcohol usage. I think it's totally reasonable to ask people to give up some of the rights they'd normally have, when those people want to operate heavy machinery in public.

My understanding is that GA pilots are not allowed to fly within 8 hours of consuming any alcohol (my understanding is that most commercial outfits have more stringent limits) - I personally think this makes a lot of sense for operating a motor vehicle, too.

It takes between 1 - 3 hours for a single mixed drink or pint of beer to be metabolized.

As a starting point I think you will agree that someone who has a BAC of zero ought to be able to drive.

The majority of drunk driving accidents are the result of people that are plowed. More disturbing by far those who ARE caught and jailed have driven hundreds of thousands of miles drunk as a skunk before actually getting taken off the road.

As BAC decreases accident rates decline towards normalcy at around 0.06 its difficult to distinguish the accident rate of those who have consumed and those who have not.

People at that point neither walk nor drive funny and are very unlikely to be discovered unless you stop and test everyone or you happen to be black or Hispanic.

Instead of tightening already reasonable standards to ridiculous levels we would save vastly more lives by actually enforcing the laws we have effectively.

>As a starting point I think you will agree that someone who has a BAC of zero ought to be able to drive.

Not if they are tired or hungover. I mean, I don't think people should drive when they are tired for other reasons, either. It's a dangerous thing, and something you should only do when you are at your best.

Alcohol is just an easy target (and an important target) because it both degrades your actual ability, while at the same time, increasing your opinion of your ability. Because of that second effect, it's especially difficult to tell when you have had too much to drive... because one of the common side effects of alcohol is an increase in confidence.

It should be difficult to drive, and it should be easy to lose the ability to drive.

>Instead of tightening already reasonable standards to ridiculous levels we would save vastly more lives by actually enforcing the laws we have effectively.

eh, we already have rules against driving tired. they just lack an objective test.

I think that if you think you can operate a motor vehicle or a gun in public at 0.06, you are not being nearly careful enough. (And I suspect the additional confidence that alcohol gives you might actually contribute much to accident rates. I know I certainly feel more confident one drink in, and confidence is deadly when you are operating weapons or heavy machinery around other people.)

You agree to these things when getting a license. It's like the EULA we never read.

If the device is wildly inaccurate why would you be obliged to prove your innocence barring other evidence of impairment.

It points very strongly toward intoxication. There is just enough false positives that they are required by the state to also take a blood test.

It's a confirmation, and when you're about to sentence someone on the spot with what is often a life changing, multi year disqualification from driving, the courts require the police to be absolutely sure.

You're usually free to refuse the blood test, but the DMV is also free to revoke your license arbitarily.

It is not that simple. Within the control group of non-smokers you need people who smoked yesterday or 12 hours before to determine if the testing is successful.

But even that is too simplist. You need to activity give a specific dose to a group with similiar profiles. You need to test with different profile groups.

Remember we are testing currently high not has been high.

The basic functionality of a breathalyzer is to take a given volume of an exhale and measure the concentration of a given particle as an indicator of intoxication. So long as an individual's results are greater than or equal to 0.08 then it becomes an unacceptable risk and they are considered intoxicated. If this process is going to test in a similar way, there is no need to test specific doses or profiles because the concentration isn't variable, it's a static amount. With alcohol, we don't consider weight, or what they had to drink, or how long they've drank so why should this be any different? All that needs to be defined is what the law considers a concentration which should represent a level where the risk reaches an unacceptable percentage.

I think maybe you misunderstood @wolco's point? I think what they are saying is that, for example, you might do all of your testing on college age males and find that it doesn't give any false positives for people who smoked yesterday but not today. But you still need to test it on 60 year old women to make sure it doesn't give false positives there. In other words, you need to test it for varying lengths of time and also to make sure that it has consistently acceptable results by race, sex, weight, age, etc.

Additionally you need to test it doesn't trigger a positive when someone had a cinnamon flavored mint before. Or a citrus one. Or ate a mushroom sandwich. Or has diabetes..etc etc

If that is indeed what they're saying, my point still stands. The blood alcohol limit has no variations for age, sex, gender, race, weight, time since last usage, or any other factor. It just goes by concentration. My point still stands. What the law considers the concentration which indicates intoxication is a metric based on what is considered an acceptable level of risk.

"It’s obvious that the police will want a device that produces more convictions, no point in disputing that." Uh, why couldn't we talk about it as adults? OP's answer below is excellent. Police want a device that will make their job most effective and profitable, with the lowest margin not only for legal repercussions, but also the lowest possibility of people like you deciding that all police officers are pure evil who just want as many convictions as possible. Doesn't everybody want their job to be like that? BLM has made some good progress (and more is needed yet) scaring some pure evil people who happen to be police officers into wanting what's good and right. Probably not prudent to worry about a new technology that might be oversensitive, especially when the first time this thing is used in a conviction by a person with a rich dad, they'll spend as much as possible throwing doubt on the research supporting it, or how the officer was trained to use it, or etc etc etc, in order to build plausible deniability in court and get the case thrown out.

> It’s obvious that the police will want a device that produces more convictions

If a defendant ever challenges the use of the device, an inaccurate (particularly, false-positive-producing) device is more likely to be thrown out discrediting the device class, not just the individual case, and potentially forcing after-the-fact dismissal of prior convictions.

So, avoidable false-positives isn't necessarily an approach consistent with maximizing convictions.

Unfortunately, it doesn't seem to be that simple in practice; this comment by edmundsato [1] has a lot of good info.

After-the-fact dismissal of convictions may seem like things eventually work out, but remember that in the meantime innocent people's lives are upended as they're thrown into the justice system.

[1] https://news.ycombinator.com/item?id=20718599

> After-the-fact dismissal of convictions may seem like things eventually work out

No, it doesn't.

But, if the police motivation is maximizing convictions that stick, it's a potentiality that reduces the degree to which a system that produces false positives meets that goal. (Unless you have a system that is as comprehensive a conspiracy as the FBI crime lab wholesale fabrication of the entire field of fiber analysis where essentially all the “experts” in the field were part of the scam...and even that eventually collapsed.)

My point is that before these scams "eventually collapse", people's real lives are caught in the crossfire.

It doesn't even have to be a big conspiracy theory. Here is an instance of a breathalyzer manufacturer pressuring researchers to stop researching whether their devices are faulty [1]. Are they actually delivering false positives? Who knows! We need to bake oversight and accountability in from the jump, not try to back our way in once too many people's lives are disrupted.

[1] https://www.zdnet.com/article/draeger-breathalyzer-breath-te...

> My point is that before these scams "eventually collapse", people's real lives are caught in the crossfire.

Yeah, I’m not disagreeing with that, nor does it seem to disagree with my point, that the consequences of the nearly-inevitable collapse makes it dubious that maximizing positive results by encouraging false positives is actually a means to the proposed police goal of maximizing convictions, if by that one means convictions that stick.

I never suggested, and also explicitly rejected, the idea that this even superficially results in a no-harm situation.

I understand. One point of disagreement that I could have made more clear is that I don't think the collapse is "nearly-inevitable" at all.

I'm also skeptical that it provides sufficient motivation to spend the money to bring the false positive rate down to X acceptable level. This is a for-profit company; they're going to try to get the lowest ratio of R&D spend to revenue that they can.

It makes me wonder how breathalyzers work. If you fail, I assume the police still need to analyze a urine sample to prevent false positives. But probable cause is established with a breathalyzer failure.

It depends on the jurisdiction. In general, the police begin with a roadside test. This is either an standard field sobriety test (walking in a straight line, touching your nose, etc) or a screening breathalyzer. If the person fails, they are arrested and taken to the station for further testing. This is either performed using a more accurate breathalyzer, or a blood test. In general, suspects can choose which test they want (blood or breath).

I don't understand the negativity in many of the comments here. I'm all for legalization of marijuana, but I actually think that the inability to test for people driving high is a very reasonable argument against legalization. I generally feel that people should be able to make their own choices, but not if those choices involve driving a 3000 pound piece of metal down the highway while impaired.

Yes, we need to be certain that this isn't giving false positives. But if anything, this is step towards more legalization efforts on the whole (and fewer people driving high).

I get that breathalyzers give you a nice simple, relatively objective number to point at, but shouldn't we be testing for actual impairment rather than the presence of chemicals which may or may not be an indicator of impairment?

Yes, in an ideal world we would do that. But by the time we come up with a perfect test that can be done roadside by police to determine driving impairment, that has very few false positives and holds up in court, we'll most likely have self driving cars and this won't be an issue anyway.

I understand that everyone reacts differently to different drugs. Dale Earnhardt can probably be a little tipsy and still drive better than me. But even if you are an above average driver, it's still immoral (and I think should be illegal) to use substances that will increase your risk of killing someone else in a car accident, even if you are having a small amount of those substances that just brings you down to average driver levels.

Car accidents are one of the leading causes of death. It's an inherently risky activity to be doing every day. But we've structured our society in a way that makes it unavoidable. Given that it's dangerous even for sober people, I don't think we should be giving people the right to drive under circumstances that make it even more dangerous.

Lots of behaviors impair your driving ability. A study found that being dehydrated caused the same number of driving errors as being drunk [0]. I'm sure it would be easy to make a field sobriety test for blood water content, but they don't, because safety isn't the real reason these laws get made. It's just public pressure to enforce moral values.

[0]: https://www.telegraph.co.uk/news/health/news/11547199/Not-dr...

That study [0] had so many flaws it's not even funny.

1. It only had 12 participants 2. One of those participants was excluded from the final results 3. They didn't test the participants' (or a separate group's) driving ability while under the influence of alcohol (they used a simulator, so it would have been fine), and so you really can't use the results to make any comparisons between dehydration and alcohol use 4. The study was funded by the European Hydration Institute

[0]: https://dspace.lboro.ac.uk/dspace-jspui/bitstream/2134/20400...

I kind of love that biased test results funded by Big Water are a thing.

Oh trust me, "Big Water" is very much a thing. I've met a guy who runs a coke bottling plant; he could hardly believe his luck. They literally just run the existing stuff dry, and it's got massive margins.

The article you cite says:

> "To put our results into perspective, the levels of driver errors we found are of a similar magnitude to those found in people with a blood alcohol content of 0.08%"

This is just comparing against the lower limit of what we legally allow. Clearly, many drunk drivers are far drunker than this.

But in any case, I don't think it's "just public pressure to enforce moral values". You can't legally drive on Ambien, but this is a prescribed drug that I don't think people have a moral issue with.

While I think the dehydration example above is probably a stretch since it's not really as bad as alcohol, there are other things that are. I'm pretty sure driving with lack of sleep is pretty bad. But it's just not practical to test for it as far as I know.

> safety isn't the real reason these laws get made. It's just public pressure to enforce moral values

Oh please. Alcohol accounts for 30ish percent of driving fatalities. Even if dehydration is equally dangerous (a big if) it’s still far less prevalent. Maybe that’s the reason there’s no law about it.

There are other things that lead to driving accidents, like lack of sleep or perhaps even needing to use the restroom. Ideally, a field test would cover most of these.

Someone just over the legal alcohol limit could be less impaired than a drowsy, sober driver, but the former would be more likely to be blamed for an accident than the latter, especially in areas with really low limits (e.g. it's 0.05% here in Utah).

>Lots of behaviors impair your driving ability. A study found that being dehydrated caused the same number of driving errors as being drunk [0].

On June 12th Colorado alone surpassed 1 billion dollars in legal marijuana sales [1]

Let's be overly optimistic and assume an average customer in Colorado has spent $5,000 that means you have 200,000 customers. That's 200,000 people potentially driving while high.

How many people, of legal driving age, are dehydrated to the point of intoxication in/visiting Colorado during that time period? I'm guessing less than a thousand, probably less than 100.


What are the chances that as you mention Dale, and I Google to find out who he is, that he would have hit the news having just survived a plane crash hours ago.

The officer should still have discretion here to let someone go if they don't feel the person is impaired. But giving them a number means they can't use that discretion the opposite way, e.g. arresting someone because "they seem like they're driving high". I imagine that kind of discretion would disproportionately affect minorities, so I see this as a win.

> The officer should still have discretion here to let someone go if they don't feel the person is impaired. But giving them a number means they can't use that discretion the opposite way, e.g. arresting someone because "they seem like they're driving high". I imagine that kind of discretion would disproportionately affect minorities, so I see this as a win.

I can't imagine a situation where an officer would employ the use of a breathalyzer and we worry about discretion. The officer used their discretion to pull the motorist over. They used their discretion to perform a sobriety test. They used their discretion to employ a breathalyzer.

Point is, if the cop wanted to let you off there are numerous occasions to do so.

"You breathalyzed positive, but you don't seem too messed up to drive to me. Drive safe."

Said no officer ever

I'm sure this varies by jurisdiction, but I really wish my local police department (in Waterloo region) were willing to put even the slightest effort toward general road safety. As a four season bike/eskate commuter who wears a gopro, I am yelled at, swerved at, I witness drivers running stop signs, exiting driveways without looking where they're going, making RTOR without looking where they are going, driving at people walking in crosswalks, and using their phones at stoplights.

I have recorded lots of videos of these behaviours, many with plate and driver face clearly visible, and my local police service just has zero interest in following up on it. There are hotspot intersections I've informed them about where they could set up shop and nail 10-20 drivers an hour for convictions with tickets ranging from $200 to $1000, but I guess they're too busy idling in parking lots waiting for that high priority call to come in.

So, driving high is totally a problem and going to be increasingly a problem, especially in Canada. But based on what I see in my community, it's not clear that the police have any interest at all in proactive enforcement, especially in service of road safety.

This isn't a silver bullet, but it will probably help. Say you are driving high right now. A cop pulls you over and suspects you are high. Now, he's got to get a blood test, which he needs to take you to a lab for and will probably need a warrant, because who is gonna consent to having their blood drawn. And most of the time, the blood test doesn't show anything useful, because unless it's done within a short time frame of you using cannabis, the THC will be broken down and it won't show that you smoked within the last few hours, only that you smoked recently, as in the last few days or weeks. So what kind of cop wants to deal with this? If you had an accurate test that could be done on the spot, it would be much easier for them. It's not like every cop will instantly be motivated, but I'm sure it'll help.

Glad to see someone else from Waterloo in the comments! I'm not sure that what local police department serves your area, but the Waterloo Regional Police Service are actually really ahead of the curve when it comes to drug impaired driving. They have more drug recognition experts per capital than almost any other jurisdiction in Canada and if I am remembering correctly they are making it mandatory to train new recruits in the standard field sobriety tests.

They should still be listening to your complaints, however. Hope you have better luck in the future.

Yes, it's WRPS for me. To be honest, I've kind of given up hope. Until the current chief is replaced there's just not much point advocating for anything.

Where is the correlation between these events and driving high being "totally a problem"

The correlation is that it's not clear that lack of a roadside cannibis test is the most pressing issue preventing cops from making our roads safer. There are dozens of things that could be better enforced (especially with more commitment to automation), but even "progressive" police departments consistently choose not to pursue most of them.

Apart from the difficulty of testing, I think the lack of simple guidelines like ‘one drink per hour’ makes it hard for cannabis users to guage their level of intoxication. I’m not sure whether it’s biologically practical, but it would be a big improvement if people generally had a reasonably easy and consistent way to determine how long they should wait as a function of how much they’ve consumed, the delivery method, their weight, their tolerance etc.

Right now it’s just completely subjective and that makes it easy for someone to justify DUI when they would never do so if similarly impaired by alcohol.

We need research and education as much as (and probably more than) enforcement.

The founder claims above that you can't detect it after 3-4 hours. Yes, there are people who will take a puff and be fine to drive an hour later. But there are plenty who won't be. As a general rule, making cannabis legal with the caveat that you can't drive within a minimum of 3-4 hours of using it, even if you feel fine to drive, seems reasonable (obviously, if you still feel impaired, it should be illegal to drive, whether it's detectable or not).

It does sound reasonable as a conservative default, but the same could be said about driving after two or three drinks—while it certainly doesn’t make anyone a better driver, good laws often try to strike a balance between public safety and not over-criminalizing extremely common and relatively low risk behavior.

Edit: What do you think would happen if we made a strict law that anything more than 0.0% BAC = a DWI? My guess is you’d end up with a lot fewer slightly intoxicated drivers, and a lot more extremely intoxicated drivers, because people will figure they might as well just drink as much as they want if they’re already breaking the law anyway.

Legalization is probably more likely to bring about good testing, with a bit of lag time, and hopefully lead to fewer people driving while high, which some people will do even when it's not legal.

Also, FWIW, if it's legal, in some places you can even order it for delivery ( http://dutchie.com ) which certainly beats being out on the road.

The first question I have is whether driving high on cannabis is less safe than sober. Then there is a question of levels of impairment. I wouldn't be surprised that someone lightly stoned is actually safer than sober due to being more patient with performance degrading the more stoned they are. Treating cannabis like alcohol is not the correct approach. I sold find it better to think of it like coffee. Some coffee before driving is fine but large jitter inducing amounts is not.

The human race is a bunch of bumbling morons half of which are also bad people.

For any new human endeavor which could negatively impact my life in any way I start with the assumption that whatever measure is undertaken will do nothing to address the actual problem AND whatever can possibly go wrong will.

From there I'm willing from there to be convinced that the people are uncommonly capable and ethical in theory.

> but not if those choices involve driving a 3000 pound piece of metal down the highway while impaired

Loads of people make the choice every day to drive while distracted, texting while driving, etc. I see that as a far greater threat that needs to be addressed, and none of those things can be "tested" for when you get pulled over.

I'm not sure I understand your point. There are lots of things that impair driving that can't be tested and are therefore hard to address. Some of them are really bad. Therefore, we should not focus on things that impair driving that can be tested?

It's not either/or. We can push for testing for high drivers and push for ways to combat and penalize distracted driving. The fact that high driving apparently can be tested for while distracted driving can't makes this a low-hanging fruit.

Because alcohol has been around for a long time in the public’s consciousness, they equate marijuana with alcohol in terms of impairment and driving. They are not comparable. Test impairment, not the presence of an arbitrary chemical in one’s breath.

Well, this simply doesn't matter. There are already tests for impairment that failing will land you a DUI regardless of your breathalyzer test levels.

I've been a daily cannabis user for over a decade. I have a prescription for this, like millions of others with prescriptions for psychoactive medications without driving limitations. Would you send someone to prison for driving because they took their Adderall that morning? Cannabis is not like alcohol in regard to impairment of motor function and decision-making under the influence. Surely the same concentrations of particulate correlate to different levels of impairment in different individuals. Of course it is possible for individuals to be impaired by cannabis to the extent that driving would be dangerous. There are many factors. I'm wary of a device that purports to determine actions as dangerous based on the the measure of some particulate in the breath.

Thank you for your feedback. It is really valuable to get the perspective of a frequent cannabis user. Cannabis tolerance is definitely a huge factor in determining whether or not someone is impaired. As a daily user, I am sure you are fine to drive after having used cannabis (although this is not legal advice :) ). However, people forget that there are significant tolerance effects for alcohol as well. There are people who can blow a 0.15% (well over the legal limit of 0.08%) and not exhibit any impairment symptoms. The key is finding a limit that allows police to identify actually impaired drivers while giving those with tolerance enough leeway to avoid being falsely charged. The scariest thing for frequent users is the blood legal limits being proposed in Canada and across the US, give that blood can have detectable levels of cannabis up to a week after abstinence. That is why one of our big focuses is finding a replacement for blood testing.

Thanks for your reply and engaging in this sort of discourse. I agree with all of your points, and also feel that technology in this area can help in conjunction with other indicators and tests to determine dangerously impaired driving. Any improvement over the existing testing methodology and legislation where some blood concentration possibly present from the week prior serves as enough for a felony conviction seems well warranted!

>The key is finding a limit that allows police to identify actually impaired drivers while giving those with tolerance enough leeway to avoid being falsely charged

Given that is an impossible statement, it sounds like you are admitting this will be used to falsely prosecute more people than it will let off the hook. This is a smash and grab that will adversely effect society, not help it. You keep comparing it to alcohol, but you should be comparing it to adderall. Do you think society needs adderall testing curbside as well?

There's nothing wrong with having a prescription for marijuana, even if the "prescription" is really just a state medical license provided by a sketchy doctor that you slip 200 USD once a year.

But please stay off the roads while you're under "psychoactive" effects (read: high) . There are LEGAL drugs that are illegal to use while operating a motor vehicle.

Hundreds of millions of adult Americans use psychoactive substances on a daily basis (SSRI, MAOI, SNRI, Caffeine, Nicotine or worse, opiates / benzodiazepines) and are under no driving restrictions or legal ramifications for doing so.

They are subject to a warning in the commercial.


Cannabis has been medically prescribed in CO for nearly 20 years. As of this year, autism spectrum disorders are a disabling medical condition qualifying for medical use, joining PTSD, seizures, cancer, glaucoma, AIDS, severe pain, and others.

https://www.cell.com/pb-assets/journals/trends/molecular-med... draws similar conclusions scientifically rather than anecdotally -

"Currently, science does not support the development of cannabinoid limits in motor vehicles drivers per se because of the many factors influencing concentration–effect relation-ships."

"There is no one blood or oral fluid concentration that can differentiate impaired and not impaired."

I'm not sure what you're on about, prescriptions for marijuana are a thing...

>Cannabis is not like alcohol in regard to impairment of motor function and decision-making under the influence.

As someone has been high a few times before, I would most definitely not agree with this

And someone who has never drank alcohol could easily fall below the BAC limits for impaired driving while still being completely impaired, after just one drink.

Great job to the founders, awesome to see more cool companies out of the UW nano program.

Curious why all the negativity, perhaps people are unaware that cannabis actively DOES impair driving to dangerous levels. Also, as this startup is from Canada I'm almost certain the mindframe of the founders is to develop a device that makes legalization EASIER, not allowing police to use it catch and arrest people on the street who they think are high.

One issue we have been dealing with in Canada is how to regulate driving after consuming cannabis. A zero tolerance policy for smoking + driving within days is unreasonable and thus will be ineffective. This device and the research behind it looks like could help regulators and police catch people who are dangerously high while not arresting those who happened to smoke much earlier.

Please cite actual statistics and studies that prove cannabis impairment danger.

“ In seven of ten studies cited, cannabis use was associated with a decrease in driving speed despite explicit instructions to maintain a particular speed, whereas under the influence of alcohol, subjects consistently drove faster. Two simulator studies showed that the tendency to overtake was decreased with cannabis use but increased with alcohol.52, 53 One simulator study and two on-road studies examining car-following behavior concluded that cannabis smokers tend to increase the distance between themselves and the car in front of them.41, 45 Other studies have found no adverse effects of marijuana use on sign detection,49 a sudden lane-changing task,43 or the detection of and response to hazardous events.”

"Epidemiological studies have been inconclusive regarding whether cannabis use causes an increased risk of accidents; in contrast, unanimity exists that alcohol use increases crash risk" - direct quote from your link.

That study is about alcohol combined with cannabis (i.e. presuming effect then striving to find a cause).

Disclaimer: I have never been a cannabis user.

"marijuana smokers tend to compensate effectively for their impairment by utilizing a variety of behavioral strategies such as driving more slowly, passing less, and leaving more space between themselves and cars in front of them."

Do you have any proof that cannabis impairs driving?

Here is a good overview of dozens of studies that have performed on subject.


The tl;dr is Cannabis absolutely impairs the core skills you use when driving, but also raises your awareness of your impairment so those under the influence tend to drive more cautiously. The result is in simulator studies cannabis shows a clear negative effect, but in functional studies, its more of a wash.

Please fully read and understand the resource you linked

> Experienced smokers who drive on a set course show almost no functional impairment under the influence of marijuana, except when it is combined with alcohol.

And the conclusion that the lack of functional impairment is due to increased awareness of impairment is merely speculation and is not based on any empirical result.

I don't even understand how this is a question in anyone's mind.

Because studies show that Marijuana results in no functional impairment in test courses? Maybe you should learn to trust data and science rather than just your preheld beliefs that aren't necessarily rooted in sound logic or reasoning.


Have you never seen anyone super stoned before? What studies do you even need beyond that? Yeah there is a scale before people shouldn't be driving, and this device will help enforce that line. It may take time and work, but better than nothing.

Once again, your personal experience and anecdotes aren't necessarily reflective of reality. Personal anecdotes are the worst form of evidence there is. Read the actual study, so that you may learn something. Your miniscule personal experience is in no way rigorous.

The study contradicts your assertions and does so in a rigorous controlled study. Obviously that holds more weight than your anecdotes or statements that have no empirical or logical basis.

From the paper you linked

> Experienced smokers who drive on a set course show almost no functional impairment under the influence of marijuana, except when it is combined with alcohol

Given that marijuana arrests disproportionally target people of color, have you considered the ethical implications of bringing your product to market? The accuracy of your device doesn't affect how or on whom it will be used.

We absolutely consider ethical implications for bringing this product to market. We currently live in a world where it's a "free-for-all", and officers establish reasonable suspicion, which leads to an arrest, without any objective evidence. We hypothesize that this is part of the reason why there's a higher number of PoC arrested. This doesn't happen with alcohol, because there is an objective device.

I'm sorry, but this is just not true. People are innocent until proven guilty. If there is no evidence, then they aren't convicted (EDIT: for the record, testimony is evidence). Adding an avenue to collect more evidence is going to cause more people to be convicted. Sure, you will probably get some people exonerated, but there is no question that you will get a larger number of people convicted. I am not going to weigh in on the ethics of that, but you should at least be honest about the repercussions of your work.

Apologies, one thing I forgot to mention is that once reasonable suspicion is established, and an arrest happens, if you aren't blowing over 0.08 for alcohol, police will request a blood test. It's possible that for frequent users, THC will show up in these blood tests even though they haven't recently smoked. If an officer screens you on our device (which only has a 3 hour window of detection) and there is no THC, they have no further reason to request a blood test. Thoughts?

(American viewpoint about this device being potentially used in America. Courts and policing is different in Canada, and so my feelings here aren't neccesarily how it would work out there)

In many (most?) states you can refuse the blood test, until they get a warrant, even though you cannot refuse the Breathalyzer. I believe this will be used as a tool to make arrests and generate probable cause which will then immediately be used to obtain a warrant and blood test, which will hold up in court much better than the Breathalyzer alone or nothing at all.

I'm sorry, but even if this product works perfect technically I see it harming more people than it helps. Throw in chance of false positives and likely hood it is used by biased individuals in a biased way (only some individuals are told to blow multiple times, etc) and I really believe this product deployed in America would have a negative impact on most people.

>It's possible that for frequent users, THC will show up in these blood tests even though they haven't recently smoked

That leaves reasonable doubt. Reasonable doubt favors the accused. If your device removes reasonable doubt, it does not benefit the accused.

The device adds reasonable doubt over the status quo in the case where a blood test shows positive for THC and the device shows negative.

Convictions are not the only way for a police encounter to be a problem in the United States. 70% of the local jail population has never been convicted of a crime: https://www.prisonpolicy.org/graphs/pie2017_jail_detail.html

Are we sure this is true? I would be curious to see the current conviction ratio (convicted / arrested) for driving while impaired by alcohol vs marijuana. If there is a lower conviction rate for marijuana currently, you might be right... but it could be that courts simply choose to believe the cops word when there is no hard evidence.

Is it that they disproportionately target PoC, or are they simply smoking and driving more often and getting caught for it? Do we really expect every single crime statistic to show a completely perfect, proportionate representation of the host population's ethnic makeup?

PoC are disproportionately pulled over by police.

EDIT: And that means you'll never get accurate numbers on consumption/offense rates. So using those numbers is fully questionable.

How do you know it's disproportionate? What if they're actually speeding / breaking traffic laws / driving unmaintained vehicles more often?

No, it is definitely that they disproportionately target PoC.

So many naysayers here, many of which probably aren't sharing the road with cannabis consuming drivers in a region where it is 100% legal like here in Canada.

I've consumed it many times, and I know how impaired I'd be behind the wheel. It terrifies me to think of all the idiots who are probably out there driving while stoned, pretending they're "perfectly fine."

EDIT: cool, these guys are around the corner from where I'm sitting (Google Waterloo) in our old office building. Best of luck!

It's legal where I live and the drivers on the road have not changed significantly. For those opposed to legal cannabis use, it's easy to blame any traffic infraction on cannabis. I don't think we have data available that backs up that hypothesis. In areas where cannabis has been legalized for recreational use, the incidence of traffic accidents has remained the same.


Not opposed to legal cannabis at all, but as a cyclist, I'm very opposed to impaired driving whether it's booze, pot, or staring at a mobile phone.

I'm a cyclist as well and impairment via cell-phone or hands-free call has been the most threatening for myself personally. And every parking lot ever is liking gambling with my life.

I'd agree - but probably because it seems to be so common compared to drunk or high people.

I have to wonder about the combination of those two -- marijuana impairment + mobile phone (or, hell, the car stereo).

In my experience cannabis just destroys my ability to context switch effectively. Other people, not so much. Electronics in the car are already a distraction, but I suspect far worse for someone impaired.

What about coffee, sugar or people driving with headaches?

Those three can really affect my driving.

Past that, if you've been awake for 18 hours, you're very likely to be impaired to the same extent as a 0.08 BAC.

Certainly. That's not a good reason to let people drive high or drunk though.

It would be a good reason to put effort into a "breath test for sleep" before other "breath test for X" methods / devices.

It would be a good reason to test for actual impairment with a clearly defined set of behaviors or lack thereof that indicate impairment.

> I don't think we have data available that backs up that hypothesis.

I think this is another key point in favor of this device. The traffic safety data that exists comes from police reports. Each officer has to key in the information when they handle an accident, so having a device like this in the hands of those officers is the first step in starting to build that kind of data set.

That's great assuming the device is accurate, precise, and repeatable. It's not clear that breathalyzers can achieve these either but the legal system loves using them as a conviction tool. This could be yet another addition to their dowsing rod toolkit.

> In areas where cannabis has been legalized for recreational use, the incidence of traffic accidents has remained the same.

Perhaps that indicates an opportunity - if there was a way to check for stoned drivers, it might have gone down.

there's plenty of literature proving that individual drivers are worse when they're high. check ramaekers' publications.

maybe you can hypothesize some weird situation where individual drivers are worse, but overall traffic is unaffected. but individual users should still want to avoid driving high, as lower overall traffic deaths will not make you feel better about accidentally killing someone.

I was an all-day pothead for 16 years with hundreds of thousands of miles behind the wheel. I had zero at-fault accidents and 2 speeding tickets during that time. I find it hard to support regulating something like THC or other metabolite threshold testing because I feel like it completely ignores the overall relationship to impairment.

Driving with an anger management issue is a much more serious problem in my experience. Why don't we test for that?

This really means nothing. There are people who drive drunk all the time who can say the same, but that doesn’t mean it is not dangerous.

I foolishly drove drunk home from shows, clubs and restaurants for about five years, and I mean drunk. Never had an accident, never got pulled over. I'm sober now and completely regret that and realize how dangerous it was. Just because you and I were capable of getting home safely does NOT mean that everyone else is. You cannot use anecdotal experiences to support this kind of argument.

Edit: I'm also an all-day pothead (yeah, I've obviously got my vices...) and I don't trust everyone to be able to react quickly or remain focused or not get paranoid when they're stoned and driving.

Clever how you use the phrase these guys to underscore your belief that what they're doing is a good thing. I, on the other hand, agree with the other commenter that "it sounds like a terrible world honestly", and I have a negative view of this startup. I would probably something formal to describe the people working there, just like I would people working at Elsevier.

I would compare it ethically to working for or investing in the private prison industry.

Ooh, that makes perfect sense.

A given level of THC affects some a lot more than others. There are people who feel extremely "high" with 20 milligrams, and others who feel nothing. I do not believe you have a solution to this problem. The only thing a police officer should be permitted to do is give a field sobriety test. These devices are going to create more problems than they solve.

Field sobriety tests are far worse than something objective like this. If a cop has it in for you, you are going to fail the sobriety test regardless of how impaired you actually are.

You can define clearly the behaviors (or lack thereof) that indicate impairment. You can make it mandatory to record these tests in case you go to court. These values spit out by the breathalyzers are arbitrary and they do not take any other and crucial factors into account.

I remember reading a story about a Grandmother who ate a strong pot brownie everyday for medical reasons and it had little noticeable effect on her.

We know there's a direct correlation between alcohol levels and driving impairment, but I've not seen evidence for this link with THC. Are there studies that have found this? (Please forgive my ignorance...)

If someone uses X amount of marijuana (what this tech can establish), do we know that this will always have effect Y on the driver?

For example I know people who are heavy marijuana smokers who can smoke a whole joint and you'd never know whereas someone right next to them will take one puff and lose their mind.

> If someone uses X amount of marijuana (what this tech can establish), do we know that this will always have effect Y on the driver?

That's not the relation we have with alcohol, either; we have an on-averagr relationship. Which is why drunk driving laws tend to prohibit both being actually impaired by alcohol regardless of BAC and having a BAC over a certain level even without any other evidence of impairment.

Drugged driving laws generally prohibit actual impairment due to any drug (including marijuana/THC), without specifying testing thresholds as an alternative basis, largely because we don't have as much testing levels vs. impairment data for other drugs.

A test could provide evidence supporting the conclusion that observed erratic behavior was impairment due to the drug without being compared against a fixed “prohibited” threshold.

Excellent point. I'm not sure how "fixed" the correlation is for alcohol though. Someone who almost never drinks will be quite impaired at 1‰ BAC, whereas someone who drinks several times a week might not be affected that much. Of course this variation is comparatively small. When it comes to THC, individual resistance really differs by orders of magnitude. Seems the body can adapt to psychoactive agents more easily than to cytotoxins such as alcohol.

As a few people have mentioned already, there really is not a foolproof correlation between "amount taken" and "degree of impairment" for any drug. Even for alcohol, frequent alcohol users can build up significant tolerance. In general, blood concentrations for THC are pretty good at identifying impairment for infrequent users (greater than 90% predictive in some studies), but are very inaccurate for frequent users with a built up tolerance.

> are very inaccurate for frequent users with a built up tolerance.

Emphasis on this.

Do you struggle with the ethics of assisting in the arrest of, in my state, 90% minorities for a crime with dubious safety grounds?

This is a really important topic, and we were hoping someone would bring it up. Our device is designed to output objective results to shift the burden of proof from subjective observation to the output of a device. We would expect the number of false positives to decrease as a result of our device.

With that being said, we're also allocating a significant amount of our resources to have full-time employees, with lived experiences, research the implications of our technology on minority communities.

What a naive answer. A more perfect device is not preventing what OP is asking you.

Either those people are breaking the law and driving impaired or not.

If they are driving impaired, then the solution to the injustice is not to let them go, but to arrest more impaired white drivers.

If they are not driving impaired, but being arrested based on the subjective opinions of the police officer, then this device can help their defense in court.

Either way, I don't see how this device is making things worse.

Are we even sure this is a problem? There seems to be no consensus on the impact of driving on THC [0].

THC has neurocognitive impacts, but those tend to be small and long lasting. It would be strange to tell users they can't drive for 30 days or longer.


It's not a problem, it's a business opportunity. Imagine being a sole manufacturer of a device every cop will be carrying... Many successful companies are making human lives miserable anyway, this is simply one more.

The science is actually pretty concrete regarding the impairing effects of THC. Because cannabis is a schedule 1 drug, it can be very difficult for researchers to get their hands on real world doses of THC. Instead, they use very low doses that are not relevant to what is actually sold at dispensaries. For a really good review of all things cannabis impairment, I would recommend looking through the following report by the Cannabis Control Commission in Massachusetts. A little long, but a lot of good information. https://mass-cannabis-control.com/wp-content/uploads/2019/01...

You claim that the science is concrete but cite no actual studies. I’m assuming that this kind of behavior is going to be a good indicator of the product’s actual effectiveness on driving safety overall.

I'm shocked that an organization called the Cannabis Control Commission published a report in favor of Cannabis Control!

I urge you to read the report. I think it relays a very balanced accounting of the facts. Its also a good place to find all the studies in one document, so I don't have to send you 100 links!

I spent several minutes looking and was not able to find those links within the 223 page report.

What do you think about the National Highway Traffic Safety Administration report to Congress? https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/documents/81...

It seems pretty clear in terms of the art of the science and the impairment observed from actual national data.

I'm sorry, but I'll have to state my discontent with your product. Firstly, I question it's usability from the beginning. How accurate is it? Can you get something similar to a BAC with it? Also how often/likely is it that a false positive will happen? More importantly I fear that the "Cannabis Breathalyzer" will become like a polygraph, which can't tell whether your actually lying or not, but is merely used as a tool by police that's used against people. Comparing Alcohol to Cannabis also isn't right. These are vastly different chemicals with different effects on people. Over ~10000 people died in 2017 from alcohol impaired driving[0], can anything remotely similar be said of Cannabis? Don't get me wrong driving under the influence of any drug can be dangerous, and is why on most prescription bottles you'll have a "Do not operate heavy machinery" warning on it, but that doesn't stop everyone on medication from driving. Prohibiting Cannabis has caused much grief in the past that this tool, without accurate results and proper use, is likely going to cause more harm than good. If anything it will probably just help increase the incarceration rate to meet the status quo.

[0] https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/...

Given there are countless substances that are hard/impossible to test for that could affect someone's ability to drive, the solution to this issue seems not to invent a new device for each substance but to come up with a more generalized test to measure someones level of impairment — reaction times are a good proxy.

Yeah, what happens when the next drug comes to legalization? A new device and a new dubious test with a 20 dollar per test charge? Maybe a cop should have a PlayStation and a driving wheel to test for impairment. Or a button that you have to press when you see something on the screen.

Interesting idea (congrats on launching) and interesting discussion here. Reading this thread has popped up some questions in my mind and I'm curious to hear thoughts:

Why do we (aka society aka the police) test for specific substance quantities at all? Really, I think, what we care about is whether someone is able to competently perform the task of driving at a given moment.

If you are unable to perform that task, then you should be removed from the road (and, possibly, punished).

Frankly, I don't really care whether you're drunk, high, tired, distracted from texting or even if you're just a plain 'ol bad driver. The net result is the same - you're an increased risk to others on (and off) the road and your risk should be mitigated.

This gets to the root of a number of related issues - the fact that different bodies react to different levels of chemicals in different ways, etc. etc.

If you're able to function at a given moment, fine by me. If your driving is compromised for whatever reason (as demonstrated by a field sobriety test), then off the road you go.

Thoughts / corrections / slap-downs?

Excellent point. The best solution to impaired driving would be a 100% accurate impairment test. The problem comes with designing and implementing such a test.

Let's start with what they have today, the standard field sobriety test. It is a pretty good test of impairment (with accuracy range between %75 to 90% depending on the study). However, there are several problems with the SFST. First of all, it requires police officers to be well trained and exercise their judgement roadside. This introduces the possibility for bias and the costs of training can sometimes be prohibitive. Secondly, the SFST cannot be administered in all conditions. A snowy day is a really bad time to be impaired, but also really difficult conditions for running a SFST.

The alternative is some kind of device that could detect the same (or different) markers of impairment as the SFST. The problem is making a device that is as accurate as the SFST, is portable, and easy to use is very difficult. If you look at attempts to date (like the Ocular DAX), these device tend to be really unwieldy and not even as accurate as the SFST. It seems like a technology that needs a little more time (maybe a decade?).

Overall though, definitely an avenue to explore.

You can test and arrest for objective things, not subjective ones.

"Who can or can't drive" is a subjective criteria. Objective criteria is someone under the influence of x or y substance.

What's subjective about a field driving test?

The reason is simply that it's impractical to do so. It's easier to run a quick BAC test, look at a number, and call it in than supervise a road test. So you can imagine there being false positives where the person fails the test but would otherwise drive safely.

Don't forget the true intent of these tests are to determine impaired driving. The criteria of "being under the influence of something" has historically been a useful analogue for that, but the question is if we can do better somehow by testing for impaired driving directly and not 2nd order metrics.

It is documented that white & black Americans consume roughly cannabis at roughly the rate, yet black Americans are 3.73x more likely to be arrested for it (figure from the ACLU). How is this device not going to contribute to that disparity?

Thanks for the comment. Do you know if these numbers of for possession arrests or impaired driving arrests? I have been trying to look for the impaired driving arrest numbers but haven't had any luck yet.

One of the major roadblocks to legalization is fears surrounding public health risks, of which impaired driving is a component. We believe that by providing a device that makes policing cannabis impaired driving easier, we can help mitigate some of those fears. In that case, we hope the device would decrease possession arrests. As to whether or not our device would contribute to a disparity in impaired driving convictions between black and white American's, I am not 100% sure. Definitely something worth considering for us.

Hey what's it matter when you're making $20/pop.

So should no one attempt to make a device that detects this because some police are racist? I doubt American racism is at the top of minds of a Canadian startup trying to help with their nation's recent legalization of cannabis, even though they will definitely want to sell to the US market.

If we are after impairment why don't we measure reaction time and motor skills?

Alchol breathalyzers are orders of magnitude easier are broadly recognized as unscientific garbage.

It would be remarkable if your research led to anything but another tool to ruin peoples lives.

It will likely be weaponized to attack groups the police dislike like minorities.

In short I think the world would be a better place if you stayed in bed.

I for one wish you the best of luck, and hope you develop an effective and accurate product. While I may have conflicting feelings about police municipalities and the justice system, the breathalyzer has overwhelmingly been a good thing, and has saved countless lives by keeping the roads safe.


- What do you think the likelihood/timeline is that these tests will eventually be comparable in speed and accuracy to alcohol breathalyzers?

- Have you yet looked into the legal implications of a cannabis breathalyzer? Does it fall under the same rules and restrictions of a standard breathalyzer?

- How rigorously are you testing for false positives? Can you tell someone who has taken drugs but they have worn off vs someone who is currently high?

- Will you be making your data open source? Companies that sell proprietary technology to police departments can notoriously complicate legal cases when they do not disclose technical limitations or the possibilities of false positives or negatives.

- Will you be restricting your product sales only to regions where marijuana is already legal? (If it's already illegal, they have other more accurate ways of establishing possession, I presume they shouldn't need this device except for nefarious purposes).

Hey! We appreciate the support, and I hope that this response will highlight the fact that we're engineers by trade, and are completely data-driven. We're not going to be selling anything, until there's the peer-reviewed research to back it up. Here's where we're at:

- Speed isn't so much of a problem. Accuracy is by-far the most important piece of this puzzle. I think it will be between 12-18 months until we see real, robust, repeatable science to discuss the accuracy of testing in breath.

- Legal implications of a cannabis breathalyzer are all based on two things: 1. use cases and 2. geographic location. Whether the device will be used for pre-arrest or post-arrest is something we're working on understanding better.

- There is a lot of work still to do on determining our false-positive rate. We're actually going to be doing an IRB approved human trial later this year, and we'll report back to you with our findings and the full report!

- Regarding open sourcing our tech- to be honest, we haven't really thought about this yet. Might be a good way improve transparency? We're definitely not opposed!

- That's also a great question. Our tech is most useful in places where it's already legal. So that's where we'll start.

Hope this helps!

This could be used routinely in placed where any drug use is illegal more easily compared to a breathe test which could result in mass arrests.

IANAL: As I understand you can't use a breathalyzer test without a warrant.

Even when driving, you have the right to revoke it (other bad things happen, like taking your license away, but you can still refuse).

Taking a random standerby and breathalyzing him without consent or a warrant would be wrongful search and seizure.

Great point. In general it differs from country to country. In Australia, they have a random testing program that allows police to breathalyze without a warrant or probable cause. However, in the US roadside breathalyzer tests are voluntary and police require probable cause (visible evidence of swerving, smell alcohol on the breath, etc) to request a test.

I think this is really cool.

I always wondered though, the way we correlate numbers to driving ability seems sketchy. Some people take multiple large dabs of cannabis concentrate - and they're barely feeling it. This is because they basically do this all day every day.

Someone like that would fail this test, despite their motor skills remaining near baseline.

It's clearly different for alcohol, because it directly increases "network latency" (if you will) of motor control and sensory inputs.

So ultimately I would like a push to improve roadside driving ability testing, regardless of suspected substance use. This covers sleepiness, dehydration, etc.

> So ultimately I would like a push to improve roadside driving ability testing, regardless of suspected substance use. This covers sleepiness, dehydration, etc.

I definitely agree with you there. The difficulty is making it sufficiently objective.

A cop has every incentive to arrest you, so we need to have a degree of empiricism to the test so that cops can't use it to arrest anyone they want.

It’s funny to imagine a cop pulling over a stoned driver and putting him behind the wheel of a racing simulator.

Does this test for edibles? If a user has THC in their blood stream but not from their lungs, will this show up? Alcohol is absorbed through the stomach, passed through the bloodstream and released through the lungs. Since THC is fat soluble, I can't imagine it interacts the same way to allow for breathalyzer testing of people who have taken edibles.

Per OP:

> We are actually testing edibles right now! Early results don't look so good, but that could be because we were using our crappy LC-MS for detection instead of our sensor. We'll keep everyone updated with how it goes!

I don’t understand how this gadget works, but if it’s detecting residual THC in the lungs from smoke or vapor, I can’t see how this improves over blood testing as a proxy for impairment; I can see how LEO would nonetheless like to have it as it further empowers roadside judgements.

I'm curious to see how you will test for this because the liver changes the chemical composition of THC and the body processes it differently than if you smoked. The THC that was eaten will show up chemically different than of it was smoked too. This looks very promising so far!

Way too many things will go wrong here, mainly that it will fall into the hands of the police.

How does this react to other forms of cannabis ingestion (edible, topical)?

Is there science behind cannabis impairing your ability to drive like alcohol or is this just a hypothesis that you are willing to make money off of?

Are you OK with your technology potentially targeting minorities and continuing the war on cannabis which was based almost entirely on racial motives in the first place?

What levels of cannabis are in your views "acceptable"?

Do you mean "LED panel" in your Police-1 product page?

Can this detect THC that has been consumed by means other than smoking? Vaporizing? Edibles? Tincture?

Please, for all of us, make sure your test set contains a wide diversity of people - doing this testing on recruits from a local college or among friends would make it very easy to bias your results for accuracy on particular populations. it's critical that your device be equally accurate on tall people, short people, white people, black people, men, women, thin, fat, and people with various illnesses or other disorders that may affect either THC metabolism or produce abnormal breath results (e.g., excess ketones in the breath for a diabetic). and don't just listen to some random person on the internet for this, find a pro.

Excellent point. This is something we have talked about internally a lot. Early on, we are really testing whichever people we can get but when we move into a full clinical trial we are definitely going to design the study to be as diverse as possible. That is why we reached out to Curebase, to make sure the professionals were involved.

It sounds nice in theory but at such minute levels, you're going to have tons of noise and variation from individual to individual. You'll be able to produce a result, but it likely won't have any bearing in reality.

In order to offset the noise you'll need to increase your sample size (volume) of air. You can't measure what isn't there, and once you get down to these levels stuff stops becoming distributed uniformly.

Have fun becoming friends with the vendors who supply the police their other technology. Must be a great crowd of people! You all can sit around and make jokes about black people and discuss your cut of civil forfeitures.

Driving with an inadequate amount of sleep is almost certainly more dangerous and ubiquitous than having consumed a normal amount of cannabis (drowsy driving even causes more accidents than drunk driving). If we're going down this road, is there a similar effort to enforce and test for a minimum amount of sleep for drivers?

In general, that standard field sobriety test (walk in a straight line, stand on one foot, touch your nose, horizontal gaze nystagmus test) is used to gauge that kind of impairment. There are some companies that are working on automating the SFST, especially the horizontal gaze nystagmus test, but it is actually really difficult to build a device that is easy and portable but is also as accurate as a police officer.

There are mandatory rest periods for drivers of commercial vehicles. For non-commercial drivers, there is no such required rest periods but you can indeed be ticketed or arrested for driving in an unsafe manner due to sleep depravation.

Thx for letting cops and other entities bust more people with your funny device.

Sorry I got absolutely no respect for this invention of yours as I know people personally who suffer from law enforcement's false positives. You'll only help them with it but I guess making money is more important today.

I'm sure this will work out for the parties who are frequently discriminated against. Safety is a concern but you sure better prepare yourself legally for what's coming.

>we're imagining a world where there are one of our devices in every police car in North America.

Sounds like a terrible world honestly.

I wonder, if we got the opportunity to talk to the folks that invented the alcohol breathalyzers, if they had the same kind of pushback? Alcohol breathalyzers help deter drunk drivers, but there is nothing currently out there to help deter cannabis-impaired drivers. There's definitely an education piece associated with this.

I see marijuana and alcohol compared a lot with various things, that's the point where I stop participating in the conversation. It's pointless to compare two drugs with wildly different effects, onsets, durations and side effects. I disagree heavily with them being used as a point of comparison when it comes to effects on motor skills, coordination and general dangerous behaviour. I've personally imbibed both enough, been around enough people intoxicated on one or the other to know they're not comparable.

Alcohol is a central nervous system depressant that that, in high doses, causes an extreme degredation to motor skills, coordination, and thought patterns and can cause a loss of conciousness.

I agree there should be safety regulations in regards to weed but, breathalyzers and typical drug and alcohol tests are not an effective way to gauge the level of cannabis intoxication for an indiviual.

Maybe, but also comparing driving under the influence of alcohol with driving under the influence of cannabis is definitely not congruent.

This gets us to a weird gray zone of.. how impaired is too impaired? Many would say that any level of impaired is not ok, and I would definitely agree. Check out what the national highway traffic safety administration has to say about this: https://feeldifferentdrivedifferent.org/

I'd rather ride with a stoned driver than a drunk driver any day. I'd also prefer a stoned driver over an elderly driver or a sleep deprived driver. And if I had the choice between a totally sober driver or a driver on stimulants, I'd take the stimulant driver.

If this was really about reducing risk on the road, we should somehow incentivize people like OP to work on the self-driving car problem, rather than come up with a device to catch stoned drivers. Think how much brain power and law enforcement time is going to be taken up dealing with stoned drivers. The rational thing to do would be to let people drive stoned, arrest those who are visibly impaired and can't perform a field sobriety test, and focus our efforts on getting AI to replace all human drivers.

-> Many would say that any level of impaired is not ok Many would also disagree, including the law which in my state allows a BAC of up to .08 to not be charged.

In general my opinion is that .08 BAC sounds reasonable and an equivalent of MJ "could" be also. But most cases that would be a huge amount of MJ, and still doesn't relate to the effects noticed at high consumption of alcohol. IE I have never seen someone smoke so much they black out and cannot control themselves. Whereas that's happening every night people go out drinking.

My view is that there is no good way to measure this universally among all people, and MJ "impaired" driving is a non-issue compared with Drunk Driving.

Should we test people for driving on caffeiene? What about after eating too much and being sleepy? These are effects on par and just judgement calls people need to make. If the officer can smell weed\finds it then that seems appropriate and enough.

EDIT: To the points below about people passing out or cops calling 911 on themselves that speaks to the incredible variety of experience people have and what someone might experience their first time with edibles. It's not comparable to the effects smoking has on regular users, and not something anyone should be doing while driving, but how do you test for that with a Breathalyzer?

Fair points but I think this testing is only about smoking? That would seem to give even less reason to support this kind of testing since it misses the most egregious cases of edibles. I think anyone would agree that people in that kind of state are in no condition to drive, but again in my experience way outside of normal usage and not something I have ever seen. If the test took that into account alright, but it seems like these breathalyzer would be detecting a far lower threshold

Double Edit: "Theyre working on it" when it comes to edibles....

Weed is also in other forms like edibles too which are quite potent. I have seen many people who have smoked excessive amounts, or had way too many edibles. I have personally working in the event medical field dealt with countless people who are puking and unconscious due to weed.

It definitely is not anywhere near as bad as other drugs impairment wise, but it definitely can be quite dangerous to drive on.

And yes, being sleepy while driving is also super dangerous.

>Weed is also in other forms like edibles too which are quite potent. I have seen many people who have smoked excessive amounts, or had way too many edibles. I have personally working in the event medical field dealt with countless people who are puking and unconscious due to weed.

Every now and then you also hear that a law enforcement officer got high and called 911 panicking, googling "cop calls 911 high" brings up a couple of Canadian officers and a Michigan officer on the first page.


If you can let that sort of judgement slip, you think there aren't people out there getting baked and going for a drive, or now that you can easily vape away just driving down the street vaping?

A friend recently passed away and after the funeral a bunch of us went back to the house they grew up in to just hang out and talk about old times. Just about everyone there was getting extremely high, forgetting what they were saying mid sentence, taking the better part of a half hour to scratch off a single scratch off ticket, having the goofy slouch where your head goes way out in front of you... and then leaving, in their vehicles still quite high.

I mean, if you can't have a conversation without completely forgetting what you were saying in the middle of a word... you can't tell me that isn't going to affect your driving. You might just sit at a stop sign for 5 minutes because you forgot it was your turn to go, but you also might be like "hey I'm gonna check Facebook" while you're driving down the interstate.

If I had to choose, I'd rather be on the road with drunk drivers than high drivers. People that are drunk often have slowed reaction time, people that are high can easily entirely forget what they are doing and start doing something else.

I disagree wholeheartedly, but even if I agreed with you that doesn't mean that this breathalyzer is a good solution:

To the points about people passing out or cops calling 911 on themselves that speaks to the incredible variety of experience people have and what someone might experience their first time with edibles. It's not comparable to the effects smoking has on regular users, and not something anyone should be doing while driving, but how do you test for that with a Breathalyzer?

Fair points but I think this testing is only about smoking? That would seem to give even less reason to support this kind of testing since it misses the most egregious cases of edibles. I think anyone would agree that people in that kind of state are in no condition to drive, but again in my experience way outside of normal usage and not something I have ever seen. If the test took that into account alright, but it seems like these breathalyzer would be detecting a far lower threshold

Edit: "Theyre working on it" when it comes to edibles....

I don't see how the argument is much different than for someone having some beers? If they have a few beers daily and blow over is this fair as it likely is not impairing them due to a higher tolerance? How is this different than if a regular weed user were to blow over, but also may have a higher tolerance?

The problem is that you can't really test for these tolerances, especially not in the field. That's why it's usually better to air on the side of caution and set a limit.

No, it sounds like a much better world than the one we're in now. Smoking pot impairs motor skills, and driving with impaired motor skills kills people.

Few people would be in favor of taking away alcohol breathalyzers from law enforcement, and rightly so. Giving the police access to cannabis breathalyzers is no different. Once they are in every police car in the world, few people would want to take those away too. This world can't come soon enough, IMO.

How is being able to accurately tell if someone is drug driving a bad thing?

I concur.

Why do you think it's good to let drugged people drive cars?

I think we need a device that will make testing people for coffee consumption easier. It has been shown caffeine negatively affects you driving ability.

> Whereas a blood alcohol concentration of 0.08% (the legal limit in most states) might result in a concentration of 208 ppm of ethanol in the breath, a similarly impairing dose of cannabis results in 0.00001 ppm of the drug in breath. [emphasis added]

From personal experience, it seems to me that cannabis and alcohol have radically different effects. How can you define a "similarly impairing dose" when they are so unlike each other?

Perhaps by comparing accident statistics for similarities in the two groups and then comparing the doses of each that lead to those similar accident outcomes?

You can also compare performance on other standard impairment measurements techniques, such as the standard field sobriety test, or driving simulators. There are a lot of studies looking at the effect of cannabis on these tests, although a lot of them suffer from really low doses. It is hard for researchers to get their hands on real world doses of cannabis for their studies because the drug is still schedule 1.

> It is hard for researchers to get their hands on real world doses of cannabis for their studies because the drug is still schedule 1.

I hear this trope a lot, but considering the number of states in the US that it’s legalized in, can you clarify why?

For one, it makes it difficult for federally funded entities since the federal government views it as illegal. Also, lots of funding for state entities comes from federal sources. I have also heard of researchers having trouble with institutional review boards that still follow the federal guidelines.


Interesting idea, that sounds like it would give some useful information. I wonder if a study like that has been done?

Awesome products and this makes so much sense given the rise of the cannabis market.

I am surprised by the amount of comments here that seem like they are more or less arguing against enforcement of DUI laws that will save lives.

I think a lot of folks here are aware of what a double-edged sword this could be. Getting impaired drivers off the road is a worthy goal, but these kinds of tools have had devastating consequences when misused by authority. Accuracy is also a major component here, and I believe all parties have acknowledged how challenging that problem is.

Have you considered not selling technology to cops?

Yes! There has been interest from safety-sensitive industries such as transportation, energy, manufacturing, construction, and oil & gas to use our device to help prevent life-threatening accidents in the workplace.

Let's modify the above somewhat: Have you considered not selling to cops in places where marijuana use is illegal? You have a nice traffic safety story for Canada, but aren't you afraid that in the US police will just "randomly" stop and test people (anywhere, not just drivers) they would like to incriminate?

Wouldn't the companies be benefited by using blood tests since they will return positive after longer periods of time? Basically, don't blood tests allow companies to say "sorry no workers compensation - you were high when that beam cut off your leg"?

But also, I have mixed feelings about this from a moral/ethics perspective. I think it's going to do more harm than good by making testing easier and more prevalent (we already have blood tests for cases where someone was injured by a driver, etc.). The good thing is it may save some regular users from being labeled as impaired versus a blood test. Outside of that small case it all seems bad for society to me..

I bet cops will the target market...

Have you considered respecting the professionals who keep us safe, and not assuming that they're all somehow bad people out to get good folks who just happen to be "in the wrong place at the wrong time"?

I think the motivations of most police to choose a career as a police aren't in line with the best interests of citizens

Why do you think this? Do you know many police officers, or are you operating off of narratives you've absorbed from elsewhere?

You'll note that most people angrily report their bad incidents with cops; when they're doing their job it goes unremarked. Not too far off from good IT support.

It's an opinion built up over repeated interactions with police. Of course the Yelp effect applies to police but even my positive interactions with police have left me with an impression that public safety and in some respects law enforcement itself is not their primary motivation for being police. In the absence of a comprehensive psychological analysis covering a geographically distributed sample of police with a large sample size, my own experiences are what I fall back on to form my opinions. YMMV.

I have but I also read the news.

Can you create a breathalyzer for biases next so we can police the cops?

Seriously, why do we need MORE police tech when current tech is already abused beyond belief?

Please rethink your values and reconsider the unintended consequences you might have by feeding into such a violent system. Or take responsibility for how you enable abuse of people using your tech.

The Draeger breathalyzer fiasco in Washington State was mentioned elsewhere in this thread. Draeger has consistently resisted attempts to make its source code public. Will you commit to publicly releasing the source code to your "cannalyzer" device firmware?

Nice name for the device! To be honest, neither of the founders are electronics or software people, we are nanotech engineers. I don't actually know how useful the source code would be for determining if our device is working as intended. We would certainly release information regarding how our device performs QC checks and have the device validated by a third party.

Can I ask why you went this way - and what the benefits are of your specific approach? With a friend having done this in the past - having sold his technology, I've been more than a little interested in this.

Currently companies like Hound Labs have a breathalyzer test with high success rates (70% according to news reports). Israel (as a country) has two different spit tests that they've been using 'in production' (i.e the police) since 2018, both apparently in the 80% range, and as a bonus handles 5 different types of narcotics. Then there's the Drager DrugTest 5000, already deployed with law enforcement agencies at (apparently) a very high success rate.

Good question, especially regarding the DrugTest 5000

There are definitely some clear competitors in this space, but we feel that non of them have really been able to address the needs of the market.

Ill start with the Draeger because it is close to my heart. This is the device that has been approved in Canada for roadside screening. This was such a massive mistake. The government gave out tons of funding for police precincts to buy these so of course they did. However, they simply are not being used. I spoke with the drug recognition expert at the first ever police precinct in Canada to buy these devices. They bought two, and the day after the Captain of the precinct told him not to use them. He put them under his desk and they have been there ever since. The problem with the DrugTest 5000 is it is the size of a microwave, needs to be on a level surface, and has accuracy issues especially with cannabis. And really, police officers hate having to swabs someone's mouth for two minutes to get a sample.

With respect to other saliva tests, some are better than the Drager, some are worse, but they all have the same kind of problems. The police hate using them because swabbing peoples' mouths is gross, time consuming, and problematic in terms of chain of custody for evidence. Police use them because they are the best road side screening tests available today, but they would drop them in a heart beat for something less invasive.

In terms of Hound Labs, we are not 100% sure what to think. We understand they have been around for much longer, but they have not been deployed in any police precincts in the US. I know they did some early pilots in California, but nothing seems to have come of them. In general, our main advantage over Hound Labs is cost and durability. Electrochemical immunosensors are very cheap and really robust. The same can generally not be said for the fluorescent approach being used by Hound Labs. In the end, we will see who can provide the best product for the police, but we are fairly confident we have the edge.

Well, I do see a lot of potential problems with law enforced using ghettos as an "arrest shop" and the like but that's not really on the technology or your company. In general it's seems like a good thing, nobody wants unresponsive people zipping around in +1 tonne metal boxes.

I'm curious about the "similarly impairing dose" though. Any good research, actual test results, etc?

I'm assuming it's response times which make me curious how the response time of a 25 year old post 3 hour cannabis smoker compares to a +70 year old on a regular day and how that compares to someone at the legal limit for alcohol.

Thanks for the comment!

Impairment is the big question surrounding the enforcement of driving under the impairment of cannabis. It varies much more than alcohol based on BMI, age, and use history. Here are a few good resources for understanding cannabis impairment and how it compares to alcohol.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2722956/ https://mass-cannabis-control.com/wp-content/uploads/2019/01...

One of the most prolific researchers in this space is Marilyn Huestis. Anything by her is really good.

> a similarly impairing dose of cannabis results in 0.00001 ppm of the drug in breath.

Would you mind citing a source? My understanding of why this has been a difficult problem thus far is that THC concentration is not inversely proportional to motor function (unlike alcohol). I.e. the drug effects people differently and simply measuring THC concentration alone is not enough to indicate intoxication or lack thereof.

This comment comes from the fact that peak THC impairment occurs 1 hour post consumption (see the NHTSA Marijuana-Impaired Driving, A Report to Congress) and our average measurement at that time for THC in breath is around 0.00001 ppm. With alcohol, the cut off for impairment is 0.08% BAC which correlates to around 200 ppm of alcohol. So concentration of THC at the time of peak impairment is 0.00001 ppm whereas the concentration of alcohol is 200 ppm at the time of peak impairment. We did not mean to say 0.00001 ppm THC = 200 ppm of alcohol. We just wanted to illustrate the magnitude different in detecting both molecules. I guess it was not well worded :(.

>Whereas a blood alcohol concentration of 0.08% (the legal limit in most states) might result in a concentration of 208 ppm of ethanol in the breath, a similarly impairing dose of cannabis results in 0.00001 ppm of the drug in breath.

Hi, I'm just curious if you have any reference to help elaborate on the similarities of imparment as it relates to negative impact on a persons abilities (especially those known to have significant impact driving preformance)?

Is there any studied or understood similarity between the level of driving imparment when breath samples measure 208 ppm ethanol vs 0.00001 ppm cannabinoids (you may have mean just THC here but it's not clear to me)?

If there is a similar increase in the likelyhood of a fatal accident when breath measures 208 ppm ethanol vs 0.00001 ppm of the devil's lettuce I'll eat my shoe!

I don't mean to dismiss any potential impact of cannabis consumption on the likelyhood of fatal accidents or injuries but I do believe the impact is often greatly misrepresented when compared to alcohol consumption.

Thanks for your comment. Here are a few research papers you might find interesting:

Ramaekers JG, Van Wel JH, Spronk DB, et al. Cannabis and tolerance: Acute drug impairment as a function of cannabis use history. Sci Rep. 2016;6(May):1-9. doi:10.1038/srep26843 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4881034/)

Veldstra JL, Bosker WM, De Waard D, Ramaekers JG, Brookhuis KA. Comparing treatment effects of oral THC on simulated and on-the-road driving performance: Testing the validity of driving simulator drug research. Psychopharmacology (Berl). 2015;232(16):2911-2919. doi:10.1007/s00213-015-3927-9 (https://www.ncbi.nlm.nih.gov/pubmed/25957748)

Micallef J, Dupouey J, Jouve E, et al. Cannabis smoking impairs driving performance on simulator and real driving: A randomized, double blind, placebo-controlled, crossover trial. Fundam Clin Pharmacol. 2018;(June). doi:10.1111/fcp.12382 (https://www.ncbi.nlm.nih.gov/pubmed/29752828)

You are totally correct that alcohol consumption results in far more fatalities and injuries than cannabis. A big part of this is how much more prevent alcohol is than cannabis. While around 70% of people report having used alcohol in the last year, only 20% report having used cannabis. However, this is changing as more and more people are using cannabis every year. I think we are going to see a long term trend were cannabis starts to close the gap with alcohol, at least where the drug is legal.

>A similarly impairing dose of cannabis results in 0.00001 ppm

Yeah this isn't going to work. The detection threshold is so low it's gonna go off if someone is smoking weed within 500 feet. There will be so many false positives it will practically be a divining rod.

Police already abuse sniffer dogs frequently, we shouldn't allow them to use another unreliable tool to arrest people.


>We haven't had enough resources to run any formal trials yet to publish data, but that is changing this year.

So, ok. See you after the trials?

How does your device work for people who have taken edibles vs smoking?

I am not a chemist nor biologist, but ethanol escapes through mucus membranes and afaik, thc does not.

So, I am curious what mechanism has thc in the breath while people are “impaired” but not while they are heavy users that haven’t had any thc for 24 hours.

Great question. The pathway by which THC gets into your breath has not been well studied that this point. That is one of the things we are actually trying to enable!

In general, it appears that it is a mix of deposition directly into the lungs and diffusion from the blood stream. Other non-volatiles, such as other drugs of abuse taken intravenously, have been detected in breath before. I would check out the research done by Olof Beck. He is fairly prolific in this space.

We are actually testing edibles right now, so we will know more in the coming months.

There is some serious negativity in these comments that I don't understand. I for one think that there is a strong need for a weed breathalyzer, and I encourage you in your efforts.

This is a fundamental and necessary part of the legalization of weed. Some people here are worried about the efficacy of such a device and the motives of partied involved - and rightly so. But consider for a moment: the cops don't need to use any sort of test or device in order to arrest you if they suspect you of smoking today. They throw you in a jail cell and let the lab do your blood work in a couple months. And that process is very imprecise! You could have used cannabis weeks ago, then driven totally sober, but it would still show up in your blood tests.

I had no idea this was such a polemic topic. Police have been doing roadside saliva-swab tests for cannabis, ecstasy and meth where I live for years now


Is it because it's a breathalyser?

My personal feeling is that lumping those three drugs in together (along with alcohol) is a blunt approach (which admittedly is often what the law favours) - I'd much rather be sharing the road with a bunch of stoners than meth heads or boozers, but the tendency here is towards zero tolerance for all impaired driving, regardless of the substance

It's a problem if it measures use instead of impairment especially where use is legal even more so if use is medical.

You'd find it pretty stupid if a breathalyzer sunk your life where you had a beer yesterday or 2 oz of beer 30 minutes ago.

That's how alcohol breathalysers work here - if it looks like you're over the legal limit you get a second, more sophisticated test.

If you're way over whatever limit they decide for THC then it shouldn't matter if you have a prescription - a medical need doesn't make you a better driver while under the influence.

But I agree with what you're saying - it's not the tool that is problematic here, but the laws that go around it. A beer yesterday seems OK. Driving tipsy is generally accepted (except in Oz in the case of novice/probationary drivers) but considering the high correlation between alcohol and driving impairment, I think it's more a testament to the alcohol lobby's strength that even a little drink driving is considered reasonable. Drinking alcohol is/should be a recreational activity, not a human right.

Some of the Australian jurisdictions in which mobile drug testing has been implemented don't see this as a problem: as well as driving while impaired, there is a separate offence for having illicit drugs in your system which is designed for cases where the user may not actually be impaired [1] [2].

[1]: https://www.legalaid.nsw.gov.au/publications/factsheets-and-...

[2]: https://www.abc.net.au/news/2019-05-06/nsw-announces-drug-dr...

You don't see an issue with this? The people have an obvious vested interest in ensuring people aren't driving impaired. This is why we effectively are able to justify effectively searching your body for things that we have justifiable reason to believe may exist and might cause you to accidentally murder your fellow citizen with your car.

Absent the motive of impairment how do we justify such a search when we wouldn't allow such a thing in your house or on the sidewalk? Presumably Australia does because its notions of civil rights are about as interesting as Alabama's notion of reproductive freedom but do you?

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