Category Archives: Breathalyzers
We all know that if someone is arrested on suspicion of drunk driving, they will be required to take a breathalyzer test, usually later at the police station. And this test result will be the primary evidence used against him in a drunk driving case.
The first problem with this is that the amount of alcohol in the blood is constantly changing — either rising due to absorption from recent drinking or, more likely, falling due to metabolism of the alcohol.
The second problem is that it is only illegal to have a .08% blood-alcohol concentration at the time of driving — not later at the police station. And this breath test may not be given for an hour or two after the driving has ended — particularly in accident cases, where the police may not arrive for some time. So the prosecution has to try to estimate what the blood-alcohol level was when the suspect was driving based upon the later test.
The third problem is that because of this, for the test results to be admissible as evidence in court they have to have been obtained within a certain period of time — in California, for example, within three hours.
But what if there was a breath-testing device which could record what the blood-alcohol level was at the time the suspect is actually driving?
Flexible Wearable Electronic Skin Patch Offers New Way to Monitor Alcohol Levels
San Diego, CA. Aug. 2 – Engineers at the University of California San Diego have developed a flexible wearable sensor that can accurately measure a person’s blood alcohol level from sweat and transmit the data wirelessly to a laptop, smartphone or other mobile device. The device can be worn on the skin and could be used by doctors and police officers for continuous, non-invasive and real-time monitoring of blood alcohol content.
The device consists of a temporary tattoo — which sticks to the skin, induces sweat and electrochemically detects the alcohol level — and a portable flexible electronic circuit board, which is connected to the tattoo by a magnet and can communicate the information to a mobile device via Bluetooth…
Clearly, the government would be very interested in requiring anyone convicted of DUI to wear such a patch for the probationary period (commonly three years).
But what if that government decided to take the next step…..and require everyone to wear these skin patches — as a condition for driving any vehicle?
The breathalyzer is the most commonly used method for testing the blood alcohol content of suspected drunk drivers in California. Yet, both myself and Lawrence Taylor have written on more than a few occasions about the inaccuracies of the breathalyzer. Such inaccuracies include, but are not limited to an inability to differentiate between blood alcohol and “mouth alcohol,” elevated temperatures causing elevated BAC readings, and certain diets causing elevated readings.
So can a person suspected of driving under the influence of alcohol in California challenge the accuracy of breathalyzers in court?
Notwithstanding the widely proven fact that breathalyzers are generally inaccurate, the California Supreme Court in 2013 ruled that scientific evidence refuting the accuracy of breathalyzers in general in California DUI cases are inadmissible.
The issue arose when a California trial court agreed with the prosecutor and excluded the testimony of a defense expert of Terry Vangelder who would have testified that breathalyzers, in general, can be inaccurate.
In 2007, California Highway Patrol pulled over Vangelder for allegedly going 125 miles per hour in San Diego. Although having admitted to consuming some alcohol, Vangelder passed field sobriety tests. Vangelder then agreed to a preliminary screening alcohol test (an optional roadside breathalyzer) which indicated that Vangelder’s blood alcohol content was 0.086 percent. Based on that, Vangelder was arrested and transported to the police station where he submitted to a chemical breath test (a required post-arrest breathalyzer). This breath test showed a blood alcohol content of 0.08 percent. Vangelder then submitted to a blood test which indicated that his blood alcohol content of 0.087 percent.
At trial, Vangelder called Dr. Michael Hlastala, a leading authority on the inaccuracies of breathalyzers.
“They are (inaccurate),” Dr. Hlastala testified before the trial judge. “And primarily because the basic assumption that all of the manufacturers have used is that the breath that [is] measured is directly related to water in the lungs, which is directly related to what’s in the blood. And in recent years, we’ve learned that, in fact, that’s not the case.”
The judge however, did not allow the testimony and Vangelder was found guilty. Vangelder appealed and the appellate court reversed the decision in 2011. San Diego City Attorney, Jan Goldsmith, then appealed the appellate court decision arguing that such testimony would undermine Californi’s a per se law making it illegal to drive 0.08 percent blood alcohol content or higher.
Unfortunately, the California Supreme Court sided with Goldsmith.
“[T]he 1990 amendment of the per se offense was specifically designed to obviate the need for conversion of breath results into blood results — and it rendered irrelevant and inadmissible defense expert testimony regarding partition ratio variability among different individuals or at different times for the same individual,” Chief Justice Tani Gorre Cantil-Sakauye wrote for the court. “Whether or not that part of expired breath accurately reflects the alcohol that is present only in the alveolar region of the lungs, the statutorily proscribed amount of alcohol in expired breath corresponds to the statutorily proscribed amount of alcohol in blood, as established by the per se statute.”
The Court went on to say that, “Although Dr. Hlastala may hold scientifically based reservations concerning these legislative conclusions, we must defer to and honor the legislature’s reasonable determinations made in the course of its efforts to protect the safety and welfare of the public.”
I’m sorry, but I read that to say, “We recognize that science is important in determining the accuracy of breathalyzers, but we’re not going to undermine the legislature because of its good intent.”
Legislators are not scientists.
The effect of the decision was that people suspected of a California DUI can no longer offer evidence that breathalyzers, in general, are inaccurate. People suspected of a California DUI can, however, still challenge the accuracy of a particular breathalyzer.
Seems to me that the California Supreme Court doesn’t want accuracy in California DUI cases.
Law enforcement continues to be frustrated in trying to prove that a possibly impaired driver is under the influence of marijuana (so-called “stoned driving”).
As recent posts on this blog have pointed out, the simple fact is that there is no scientifically valid method for measuring marijuana and its effect. The current method involves drawing a blood sample from the person after the suspect is arrested and analyzing it for marijuana — or, more accurately, for the presence and amounts of the active ingredient, THC (tetrahydrocannabinol), in the blood.
But there are two primary problems with this. First, the marijuana measured may well be inactive and still present in the body from ingestion days or even weeks earlier. Second, there is no generally accepted scientific evidence as to what levels of THC can cause sufficient impairment to the ability to safely operate a motor vehicle. See, for example, my previous post Identifying and Proving DUI Marijuana (“Stoned Driving”).
The latest attempts for a quick-and-easy way to prove “stoned driving” involve developing a “marijuana breathalyzer” — a device that will test for THC on the breath, as is done for alcohol with current breathalyzers. To date, these have proven inaccurate and unreliable. See previous posts Can Breathalyzers Measure Marijuana? and Is a Marijuana Breathalyzer in the Offing?
Today, a company claims to have finally developed the long-hoped-for answer to law enforcement’s dilemma…
Pot Breathalyzer Hits the Street
U.S. News & World Report. Sept. 14 – American police have for the first time used a marijuana breathalyzer to evaluate impaired drivers, the company behind the pioneering device declared Tuesday, saying it separately confirmed its breath test can detect recent consumption of marijuana-infused food.
The two apparent firsts allow Hound Labs to move forward with plans to widely distribute its technology to law enforcement in the first half of next year, says CEO Mike Lynn. Lynn, an emergency room doctor in Oakland, California, also is a reserve officer with the Alameda County Sheriff’s Office and he helped pull over drivers in the initial field tests, none of whom were arrested after voluntarily breathing into the handheld contraption…
The technology, if all goes according to plan, will be welcomed by both sides of the pot legalization debate, those who fear drugged drivers and reformers outraged that pot users in some jurisdictions are subjectively detained and forced to undergo blood tests that don’t prove impairment, especially in frequent users….
There’s a two-part testing challenge now: confirming with laboratory equipment that the device gives accurate results, and then correlating specific measurements (given in picograms of THC) with levels of intoxication, a challenge that will include sending stoned drivers on an obstacle course — something already done informally….
Hound Labs, of course, isn’t the only company that sees an opening as U.S. states increasingly regulate sales of marijuana for recreational or medical use, but it is ahead of the curve, beating another company aiming to introduce a marijuana breathalyzer, Cannabix Technologies….
Hmmmm…..Might there a conflict of interest when the CEO is a reserve police officer involved in field testing his own product? And how can an indirect analysis of THC on the breath done in the field be more reliable and accurate than directly analyzing it in the blood in a laboratory?
Profit and politics has always trumped science and truth in the DUI field. See my post DUI Laws Overrule Scientific Truth.
Of all the questions I get about what to do and what not to do during a California DUI stop, the question about whether a person has to give a breath sample after a DUI stop is among the most common of the questions.
Strangely enough, the answer is both “yes” and “no” depending on which breath sample we’re talking about.
When law enforcement pulls someone over, chances are they already think the person is driving under the influence. However, in order to arrest them for a California DUI, law enforcement needs probable cause. This means that the officers must have facts that would lead a reasonable person to believe that the person is driving drunk. In other words, the officers cannot just arrest someone on the hunch that the person is driving while under the influence. They need facts to suggest that the person is actually driving drunk.
The officers get the probable cause, or facts, through their own observations and when the driver performs and fails the field sobriety tests. In addition to the field sobriety tests that people typically think of, there is the preliminary screening alcohol (PAS) test. This is a roadside breathalyzer that is also considered a field sobriety test. And like the other field sobriety tests, the PAS test is optional. If the PAS test shows that a person has alcohol in their system, then the officers have the facts that would suggest that the person is driving under the influence.
According to California Vehicle Code section 23612(h), the PAS test “indicates the presence or concentration of alcohol based on a breath sample in order to establish reasonable cause to believe the person was driving [under the influence]…[it] is a field sobriety test and may be used by an officer as a further investigative tool.”
The officer who makes the stop, by law, must advise the person that the PAS test is optional. California Vehicle Code section 23612(i) states that “If the officer decides to use a [PAS], the officer shall advise the person that he or she is requesting that person to take a [PAS] test to assist the officer in determining if that person is under the influence. The person’s obligation to submit to a [chemical test under California’s Implied Consent Law] is not satisfied by the person submitting to a [PAS] test. The officer shall advise the person of that fact and of the person’s right to refuse to take the [PAS] test.”
If the PAS test detects alcohol in the person’s system, they’ll likely be arrested for a DUI. Once the person is arrested, they must take a chemical test which can either be a breath or a blood test according to California’s Implied Consent Law.
California Vehicle Code section 23612(a)(1)(A) sets forth the Implied Consent requirement. “A person who drives a motor vehicle is deemed to have given his or her consent to chemical testing of his or her blood or breath for the purpose of determining the alcohol content of his or her blood, if lawfully arrested for an offense allegedly committed in violation of [California’s DUI laws].”
In other words, if you’re licensed to drive in California, you have impliedly consented to give either a breath or a blood sample when you are lawfully arrested on suspicion of a California DUI.
The key word here is “lawfully” arrested. If the officer did not observe any poor driving and the person does not perform any field sobriety tests including the PAS test, the officer may not have the probable cause to arrest the person. And if the officer does not have probable cause that the person is driving under the influence, yet they arrest the person anyways, the arrest is no longer lawful.
When an arrest is unlawful, all evidence obtained after that arrest, including the results of the chemical test are inadmissible.
As you can see, it can be rather complicated. So simply put, you do not have to take the pre-arrest breathalyzer called the PAS test, but you do have to take a post-arrest chemical test which could include a breathalyzer.
I’ve written here in past posts about the difficulties of trying to use a breathalyzer on a driver to determine whether he is under the influence of marijuana. See Is It Possible to Prove Driving Under the Influence of Drugs?. As a study authored by Dr. Jim Hedlund, formerly a senior official with the National Highway Traffic Safety Administration, has concluded:.
The relations between a drug’s presence in the body, its concentration, measured in blood, breath, saliva or urine, and its
impairing effects are complex and not understood well. A drug may be present at low levels without any impairing effects. Some
drugs or metabolites may remain in the body for days or weeks, long after any impairment has disappeared (Berning et al., 2015;
In particular, marijuana metabolites can be detected in the body for weeks after use (Berning and Smither, 2014).
On the other hand, concentrations in the body of some drugs decrease rapidly while impairing effects persist. For marijuana,
THC concentrations fall to about 60% of their peak within 15 minutes after the end of smoking and to about 20% of their peak
30 minutes after the end of smoking while impairment lasts for 2 to 4 hours (Kelly-Baker, 2014; Logan, 2014).
In addition, individuals differ in how their bodies absorb and metabolize a drug. In experimental settings, wide ranges of drug
concentrations produce similar levels of impairment in different individuals (Berning et al., 2015). NHTSA’s observation is generally
accepted: “At the current time, specific drug concentration levels cannot be reliably equated with a specific degree of driver
impairment” (Berning et al., 2015). GAO (2015) agrees: “identifying a link between impairment and drug concentrations in the body,
similar to the 0.08 BAC threshold established for alcohol, is complex and, according to officials from the Society of Forensic
Toxicologists, possibly infeasible.”
Will science and profit-hungry corporations ever be able to produce a breath-analyzing device that can accurately and reliably measure the amount of marijuana in a a driver’s blood? Doubtful, but not for lack of trying. The following is from a recent edition of Forensic magazine:
“At the same time that marijuana use is growing dramatically, law enforcement has been impeded by the lack of tools to help identify stoned drivers and get them off the road,” according to the company Hound Labs.
Now, the company is claiming they’ve created a technology capable of detecting THC (tetrahydrocannabinol) levels below 500 pg in a breathalyzer test. According U.S. News & World Report, the technology will be tested early next year in clinical trials.
“Measuring marijuana is not a simple extension of the technology in current alcohol breathalyzers,” according to Hound Labs. “The approach used in an alcohol breathalyzer won’t detect THC molecules in lungs because THC requires a scientific method more than a million times more sensitive than one needed to measure alcohol. Until now, very large, expensive and specialized detection tools were needed to detect THC in breath.”
The company’s CEO Mike Lynn said the law enforcement version of the product will sell for “well under a thousand dollars,” and the commercial consumer version will be even less, reports the U.S. News & World Report.
If true, this would be quite a break-though. If true….