Frequently Asked Questions
Scientific & Technical
A mouth alcohol effect can be caused anytime alcohol is consumed, or it can occur with burping, belching, or regurgitating alcohol-laden fluids into the mouth. Mouth alcohol does not last a long time — no more than 15 minutes — but if it is present it can create a very high false reading.
Operators of evidentiary instruments in the police office are required to observe a driver for at least 15 minutes before each breath test to ensure there is no burping, belching or consumption of alcohol that could produce a mouth alcohol effect.
ASD (approved screening device) operators are not required to conduct a 15 minute observation period before an ASD test. However they are required to determine when alcohol was last consumed and will ask the driver for this information. If there has been drinking within the previous 15 minutes, an officer should add an appropriate amount of time so that there are 15 minutes from the time of the last drink to the time of the test.
Safe drivers are preoccupied with guiding the car properly through the lane of travel, but they must also scan the roadway and area ahead for cars, pedestrians, and any other hazards.
Normally we can perform any driving task easily and safely, but some driving tasks are more difficult than others. Driving down a lightly traveled road in daylight in good weather and with little cross-traffic can be an easy drive. But driving in downtown Vancouver on a rainy winter evening at rush hour in heavy pedestrian and car traffic is a very different experience.
Driving mistakes can happen especially when the driving conditions are challenging. They can also happen when we are distracted by other tasks, such as talking to a passenger or using a cell phone. Driving errors also happen when our capacity to process information is diminished by the presence of impairing substances in our body, such as alcohol.
The effect of alcohol on driving has been studied for decades, and it is well established that alcohol impairs our attention, comprehension, and judgment. These effects cause drivers to miss important information from the driving environment and to take greater risks while driving. Moreover, alcohol slows the rate of information processing in the brain and this can result in a delay in responding to an emergency situation while driving.Impaired drivers are more likely to make errors when the driving task is difficult than when the driving is straightforward and easy. The most difficult driving task may occur when an emergency situation arises requiring the driver to respond very quickly and appropriately.
Lastly, it is important to remember that impaired drivers do not always crash. Moreover, sometimes an impaired driver who is involved in an accident did not cause the crash and is not at fault. Likewise, sober drivers with no alcohol and zero BACs can make driving errors that lead to a crash.
For most people, the impairing effects of alcohol at BACs of 30 mg% or less are barely measurable and the risk of a crash is low. But the crash risk increases rapidly as the BAC rises. At BACs of 50 mg% drivers are 1.4 times more likely to be involved in a crash as a sober driver; the risk increases to 2 times the sober driver at 70 mg%; while above 100 mg%, the risk increases dramatically and almost exponentially.
Forensic Alcohol Experts prepare the educational materials used to train police officers in the use of both the evidentiary and the ASD instruments, and they also perform a lead role as instructors. As a consequence of their scientific backgrounds and their oversight of the training courses, they are often asked by Crown counsel to provide scientific and technical reports evaluating the reliability and accuracy of breath or blood test analyses or to give an opinion on the operation of a breath test device before the courts.
Forensic Alcohol Experts are often asked to calculate the BAC of a person who has consumed a specific amount of alcohol over a specific period of time. This is called a “drinking pattern calculation”. These calculations can determine if the drinking described by the person is consistent with the BAC result from a blood or breath test, and can be used to refute or confirm a blood or breath test.
Independent Forensic Alcohol Experts, not currently affiliated with a police laboratory, can review documents in an impaired driving investigation to determine if there are errors in the breath or blood test analysis, or if a drinking pattern calculation might be useful.
1. The Zone of Impairment (30 – 100 mg%)
A person with a BAC in the range of 30 – 100 mg% may exhibit few of the outwardly observable effects of alcohol consumption. These outward effects could be: watery and bloodshot eyes; flushed face; an odor of liquor (depending on the beverage consumed). These observable effects may occur at BACs of less than 80 mg%, but become more common as the BAC rises beyond 100 mg%. If a person was impaired by alcohol, but not intoxicated by alcohol, you might not notice anything unusual about that person (other than some of the symptoms indicated above) because the impairing effects of alcohol are inward effects. In fact, a driver who is impaired but not intoxicated might outwardly appear to be sober. The impairing effects of alcohol include decreased comprehension, attention, and judgment leading to an impaired ability to judge the risks associated with any particular activity (such as driving). Impairment also causes decreased visual functions such as decreased visual acuity, depth perception, and peripheral vision. Obviously, if you were to look at a person who is impaired you could not SEE that their comprehension, judgment, and attention were affected, nor that their visual functions were diminished.
2. The Zone of Intoxication (100 – 300 mg%)
As the BAC rises beyond 100 mg%, a person becomes intoxicated by alcohol as well as impaired. At these higher BACs we start to see the signs and symptoms that most people associate with drunkenness. For the average social drinker, we see balance and speech problems starting at BACs of about 150 mg%, and for people unaccustomed to the effects of alcohol or having a low tolerance to alcohol, we see these effects at lower BACs. As the BAC increases beyond 150 mg%, the balance and speech problems become more common and more severe. At BACs starting around 200 mg%, symptoms in the average person increase to staggering gait, lurching or reeling, mental confusion, emotional instability, and problems with memory. At 250 – 300 mg%, people can become stuporous or comatose.
3. The Zone of Death (over 300mg%)
Death can occur at BACs of 300 mg% or more due to depression of the respiratory centre of the brain.
Calibrators check FST and AS IV accuracies by analyzing a sample from an alcohol standard solution with a known amount of alcohol, instead of analyzing a breath sample from a person. The result displayed by the device must be sufficiently close to the known value of the alcohol standard to ensure the device is properly calibrated. Occasionally, the Calibrator will need to adjust the accuracy of the device because the result of this test is too far from the known value. The test is then repeated to make sure the adjustment was done correctly. Usually, though, the screening devices do not require an accuracy adjustment.
Following a successful accuracy check, the Calibrator completes a Certificate of a Qualified ASD Calibrator (for the AS IV) or a Certificate of Qualified Alco-Sensor FST Calibrator (for the FST) identifying the screening device by serial number, and the alcohol standard by lot number. These important documents certify the device was found to be functioning correctly at the time of the accuracy check.
The alcohol standard solution used by the calibrator must be analyzed by an RCMP Forensic Laboratory Analyst and be legally certified a “suitable solution” as defined by the Criminal Code of Canada. The standards are identified by manufacturer name, lot number, and expiry date and this must be accurately recorded in the certificates prepared by the Calibrators. Only these “suitable solutions” are used as alcohol standards.
These certificates are submitted to RoadSafetyBC and become part of the disclosure package of information that is provided to drivers or their legal counsels when an IRP review is requested. These certificates are important documents that determine if the device was functioning correctly at the time of the accuracy check. Certificates contain important technical information that must be recorded accurately and errors or omissions in the certificate will lead to a revocation of the IRP.
Like the AS IV, the FST uses fuel cell technology.
When taking a breath sample from a driver with the FST device:
1. The police officer starts a test sequence by pressing the power button of the FST. The device will display an internal temperature that must fall within an acceptable range, followed by an air blank check that must give a zero reading. The sequence continues displaying WAIT until the device is ready to accept a sample by indicating BLOW and a flashing icon of a person’s head.
2. Qualified operators of the FST are trained to provide specific instructions of how to blow into the device and drivers should be advised to:
“take a normal breath in, seal your lips around the mouthpiece, and blow continuously through the mouthpiece until I tell you to stop”
3. When the driver starts to blow into the device, the message BLOW will disappear and be replaced by one, two, or three dashes. If the flow of breath from the driver is of sufficient force and duration, the breath sample will be analyzed, and the device will display:
– a number for a BAC of less than 60mg%,
– the message WARN, for a BAC of 60 – 99 mg%,
– the message FAIL, for a BAC of 100 mg% or higher.
4. If the breath sample is not accepted by the device, one of four different messages will be displayed: Flow LOW, Flow INS, Flow HI, & Flow CUT, depending on what the problem was with the breath sample. If the sample is not accepted on the first try, the device will automatically return to BLOW and the flashing head icon so that another blow can be attempted. There are up to three opportunities to blow during a single test sequence. If a breath sample is not accepted by the third attempt, the sequence ends. A new test sequence will have to be started before another breath sample can be attempted.
5. The test result will be shown to the driver because the FST does not produce a paper report. If the result of the breath test is a WARN or a FAIL, the officer must offer the driver a second breath test on another handheld screening device. This second test is optional to the driver.
6. The police officer will write down the results and details of the breath test. The officer will also include a brief description of the device operation, and the way in which the breath sample was, or was not, provided. These details will be recorded in the IRP narrative, as well as in the Report to Superintendent. This evidence can be very important in supporting any FAIL, WARN, or Refusal IRPs. Sometimes the police officer will make an error, leave out important details, or provide confusing descriptions of device messages – leading to concerns the device was not being operated properly or was not functioning properly.
7. Not every police officer may operate the FST. All qualified users of the device must successfully complete a training course and must indicate in the documentation they are a qualified operator of the FST.
The AS IV is based on fuel cell technology.
When a person drinks alcohol, it is absorbed into their blood and then passes into their breath. If the breath sample is captured by the AS IV fuel cell, an electrical current will be created that can be measured. The higher the current, the higher the amount of alcohol in the blood.
Here is the sequence of events when a police officer takes a breath sample from a driver on the AS IV device:
1. The police officer must commence a test sequence on the AS IV (which includes a temperature check and other instrumental self-checks) before the device displays TEST and is ready to take a breath sample.
2. The driver will be asked to blow into the AS IV.
3. As the driver blows, the device can display a number of symbols and messages, such as +, ++, NoGo, VOID, or others.
4. If the flow of breath from the driver is of sufficient force and duration, the breath sample will be analyzed, and the device will display one of the following:
– a number for a BAC of less than 60mg%,
– the message WARN, for a BAC of 60 – 99 mg%
– the message FAIL, for a BAC of 100 mg% or higher.
5. If the breath sample is not of sufficient force and duration, it will not be accepted by the AS IV. The device will automatically return to “TEST” so that another breath sample can be attempted. There are up to three opportunities to blow duting a single test sequence. If a breath sample is not accepted by the third attempt, the sequence ends. A new test sequence will have to be started before another breath sample can be attempted.
6. The test result will be shown to the driver because the AS IV does not produce a paper report. If the result of the breath test is a WARN or a FAIL, the officer must offer the driver a second breath test on another handheld screening device. This second test is optional to the driver.
7. The police officer will write down the results and details of the breath test. The officer will also include a brief description of the device operation, and the way in which the breath sample was, or was not, provided. These details will be recorded in the IRP narrative, as well as in the Report to Superintendent. This evidence can be very important in supporting any FAIL, WARN or Refusal IRPs. Sometimes the police officer will make an error, leave out important details, or provide confusing descriptions of device messages – leading to concerns the device was not being operated properly or was not functioning properly.
8. Not every police officer may operate the AS IV. All qualified users of the device must successfully complete a training course and must indicate in the documentation they are a qualified operator of the Alco-Sensor IV DWF.
The Intox is the latest generation of breathalyzer and is based on the same fuel cell technology as used in handheld screening devices. But it has increased reliability over the handheld devices; additional components and software are able to detect mouth alcohol or other interfering substances and then stop the test sequence. This prevents the Intox from giving a false test result.
The Intox performs both a blank test and an alcohol standard test with every breath test, and all these results are printed on a permanent paper test report. This instrument is highly automated to prevent operator errors, and will permanently record all status messages.
Intox breath tests are performed following the Canadian Society of Forensic Science Alcohol Test Committee recommendations for evidentiary breath tests. The most important of these recommendations require:
– the taking of two breath tests with a 20 mg% agreement of each other,
– performing alcohol standard tests at the same time as the breath tests,
– and, adhering to a 15 minute pre-test observation period.
To be certified to operate this instrument, a police officer must successfully complete a five day training course, and then must successfully complete an annual proficiency test to maintain certification. Operators are designated a Qualified Technician in the province in which they operate the Intox EC/IR II.
While portable and evidentiary instruments may be equivalent in accuracy, they are not equivalent in reliability. An Intox test result is more reliable than an ASD test result because there are more safeguards in both the test procedure and built into the instrument. For instance, the Intox can detect the presence of mouth alcohol and then stop the breath test sequence, but the small handheld devices cannot do this. The Intox procedure requires a 15 minute observation period before each breath test so that potential mouth alcohol contamination of the breath sample is eliminated; the ASD test procedure does not require this. The Intox procedure requires an alcohol standard test at the time of each breath test to ensure the breath test is accurate; again, the handheld ASD procedure does not require this. The Intox device is a highly automated instrument that minimizes operator errors and, at the end of the test sequence, a printed report is produced verifying the proper procedure was followed by the operator; in contrast, the ASDs have no printed verifications or reports.
Omitting the observation period or the alcohol standard test in an evidentiary Intox breath test would be a serious procedural error, jeopardizing the likelihood the breath test result would be used as evidence in a criminal impaired driving trial.
ASD test results have been acknowledged by the Supreme Court of Canada (R vs. Goodwin) as less reliable than evidentiary breath tests. But, while it is correct to say that ASD tests are less reliable, it is incorrect to say ASD tests are unreliable – generally ASD tests are reliable. However, the circumstances of the test and the operation of the device should be closely examined to ensure that any particular ASD test is both accurate and reliable. This is where a Forensic Alcohol Expert can help.
Impairment occurs at lower BACs than intoxication. Everyone starts becoming impaired at BACs in the range of 20 – 80 mg%, but there may be few, if any, observable symptoms at this range. Often, you can’t look at a person and see that they are impaired. However you can see when someone is intoxicated by alcohol; for the average social drinker these observable effects on speech and balance start to occur at BACs of about 150 mg%. Therefore, if a person is slurring and has balance problems because of alcohol in their blood, we can conclude they are both impaired and intoxicated.
The number and severity of symptoms (both observable and unobservable) increases along with a person’s BAC, but there can be significant differences in the presentation of symptoms for different individuals. People who regularly become intoxicated, or who regularly consume large amounts of alcohol, may develop a tolerance to alcohol. Such a drinker may require a higher BAC to exhibit the same symptoms that an average social drinker exhibits at a lower BAC. Conversely, a person who drinks alcohol infrequently may show intoxication symptoms at lower BACs than the average social drinker.
Other observable effects from alcohol might include an odour of liquor (depending on the type of alcohol consumed), watery eyes, flushed face, and bloodshot eyes. These effects can occur at much lower BACs than the speech and balance effects, and can appear in some people at BACs less than 80 mg%. These other observable effects become more common as the BAC rises, but sometimes may have causes other than the consumption of alcohol and therefore may occur in people who are neither impaired nor intoxicated.
Police are trained to make careful observations of suspected impaired drivers and to record any symptoms of alcohol consumption or poor driving in their notebooks and in any narrative describing an incident. The police narrative is one of the important documents to be considered by the RoadSafetyBC adjudicator during the IRP review. Poor driving, difficulty producing documents, or speech and balance problems are often seen as evidence corroborating high BACs and an ASD FAIL, while a lack of these symptoms may be consistent with lower BACs.
The minimum flow required is approximately 12 liters per minute which may sound like a lot but, for the average person, is very easy to provide. Sometimes people with diminished lung capacity have difficulty blowing into either the ASDs or Intox devices. Police officers may ask people who are having difficulties providing a breath sample if they have lung disease or if there is another reason for the problems.
The purpose of the observation period is to eliminate the possibility of alcohol in the mouth being measured as alcohol from the breath. If this were to happen the breath test result would be too high. The test subject is observed for at least 15 minutes before the evidentiary breath test to ensure the subject does not consume anything, burp, belch or regurgitate; if so, the observation period must be re-started.
mg%: milligrams of alcohol in 100 millitres of blood
80 mg%: legal alcohol limit in Canada for criminal prosecution
ASD: general term for any Approved Screening Device
Intox: Intoximeter EC/IR II which is an Approved Instrument for measuring alcohol levels, usually in a police station
AS IV: Alco-Sensor IV DWF, which is an Approved Screening Device, used for roadside alcohol screening in British Columbia
FST: Alco-Sensor FST which is an Approved Screening Device, used for roadside alcohol screening in British Columbia