“What should I do if police investigate me for impaired driving? Do I have to blow?”

December 20, 2014

As a criminal defence lawyer who does a great deal of work defending accused persons against impaired driving charges, people are always asking me what they should do if they ever get stopped by police for impaired driving. More specifically, I’m usually asked about whether they have to blow into a breath machine if the police tell them to, or whether they should blow or not. Unfortunately, general advice on that issue is difficult to give, and, as I will explain below, a lawyer who values his licence to practice is actually limited in the kind of answers he or she can give to such questions. However, I can easily outline the immediate consequences of failing to provide a breath sample if police make such a demand.

There are two kinds of breath demands that the police can make. One is the “roadside test” or “screening demand”, which is a demand that you provide a breath sample into a handheld screening device at the scene of the investigation. An officer can make this demand if he has “reasonable suspicion” to believe that you have any alcohol in your body. It is a very low legal test. If the officer smells the odour of an alcoholic beverage on your breath, or if you admit to having consumed any alcohol that evening, the test usually is met and the officer has a lawful basis for making the demand. These screening devices are usually calibrated to give a “fail” reading if they determine that your blood alcohol concentration is at least 100 mg of alcohol in 100 ml of blood. A fail therefore tells the officer that you are driving while over the legal limit of 80 mg of alcohol in 100 ml of blood, and gives the officer reasonable and probable to arrest you for “Over 80”, and to demand that you provide further breath samples into an approved instrument. This is the second type of demand, described below.

The second kind of breath demand is often referred to as the “breathalyzer demand”, the “Intoxilyzer demand”, or the “instrument demand”. This is the demand that requires you to accompany the officer to a police station to provide breath samples (sometimes the facilities for this testing are actually on scene at RIDE programs). The tests are conducted by a breath technician using a machine which sits on a desk, classified under law as an “approved instrument” for this kind of breath testing (the newest machine being used by police these days is the Intoxilyzer 8000C). The technician requires two valid samples in order to get a proper reading. This instrument is supposed to determine your exact blood alcohol concentration, and the results can be used as evidence in your trial to prove that you were “Over 80” at the time that you were driving.

Are you required by law to provide these breath samples when police make these demands? The safest answer I can give you is "yes". If an officer makes one of these demands, with a valid legal basis for doing so, then you have to comply. If you do not, you will be charged with failing to provide a breath sample, an offence which carries the exact same minimum penalties and consequences to your licence as the offences of “Over 80” or impaired driving. Essentially, if found guilty of failing to provide a breath sample, you will be treated by the court as if you had been found guilty of drunk driving. Furthermore, the fact that you refused to provide a breath sample can be used to support an inference that you were impaired by alcohol at the time and didn’t want to be found out. This means that your refusal could be used as evidence of two offences that you could be found guilty of: failure to provide a breath sample AND impaired driving.

But what if the officer does not have a valid basis to make the demand? Do you have to comply? The answer to that is 'no', you do not have to comply with an invalid demand. Indeed, I have won countless trials for clients charged with failure to provide a breath sample on the basis that the officer did not have the required legal grounds to make the demand, or that some other circumstance invalidated the demand. However, there is almost no way for you to know at the time the demand is made whether it is legally valid or not. Furthermore, if the investigation is following proper procedures, you do not even have the right to get advice from a lawyer before providing the a sample into a roadside screening device (but you should always ask the officer if you can do so, because he or she may allow it). This means that I usually won't have the opportunity to give you any advice about the screening demand when you’re sitting at the roadside, considering what you should do. Even if I could, there’s practically no way that I would be able to get enough information from you to determine if the demand is valid or not.

The same goes for giving advice about breath testing at the police station. You have the right to speak to your counsel of choice before the instrument breath testing, and you should always exercise that right, but I still would not likely be able to get enough information from you to confidently determine that the demand is invalid and that you do not have to blow. And, if I can’t say for certain that the demand is invalid, then I am taking a risk myself in advising you not to blow. Technically, in telling you not to blow, I could be advising you to commit the criminal offence of failing to provide a breath sample, and it is a crime for anyone (lawyers included) to counsel another person to commit an indictable offence. Giving advice to not blow is therefore an immense risk to the lawyer and to you.

In summation, if you refuse or fail to provide a breath sample, you may deprive the police of evidence of your blood alcohol concentration, but you will surely face a charge of failing to provide a breath sample – an offence with the exact same minimum penalty and consequent driving restrictions. You may have a defence to a refusal charge if the demand was invalid, but if you instead decided to comply with the demand and provide the breath sample, I would still be able to challenge the admissibility of the breath readings based on the invalidity of the demand. In either case, you may still additionally face the charge of impaired driving, which is not dependent on the police obtaining breath samples from you, but is an offence which may be proven in part by a refusal to provide a breath sample. I’m not giving out any general legal advice in this issue, but the legal information that I’ve provided here should should make it obvious as to what your best course of action is if you are ever faced with a breath demand by police. 

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