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Roadside tests: Breathalyzer, Standardized Field Sobriety Test, and Oral Fluid Test

Region: Ontario Answer Number: 771

Roadside alcohol screening tests

To test a driver’s alcohol consumption, the police have the legal right to administer certain tests at the side of the road after someone has been pulled over: a breath-screening test, and the Standardized Field Sobriety Test.  They may also demand an oral fluid (saliva) sample to test for drug impairment (see drug-impaired driving tests below).

The roadside breath-screening test helps the police determine the amount of alcohol in a person’s body. The breath test is done using an Approved Screening Device (ASD) such as a breathalyzer. A breathalyzer provides an exact reading of the blood alcohol level.

Police may also ask a driver to perform a Standardized Field Sobriety Test, or SFST, which tests whether his or her’s ability to drive has been impaired by alcohol and / or drugs. For example, they may be asked to walk in a straight line. If an ASD is not available, the police will conduct a SFST instead.

When can the police request a roadside breath test?

Until recently, the police had to have a reasonable suspicion that alcohol had been consumed in order to demand a driver perform a roadside breath test. This may be due to observations made by the police, such as your appearance, your physical movements, whether you or your car smell of alcohol, and your answers to questions. Although you are not required to respond to questions by the police, failing to do so may lead the police to suspect you have consumed alcohol, and they will likely require you to provide a roadside breath-screening sample.

Mandatory alcohol breath screening tests

Under recent changes to Section 253 of the Criminal Code (as per Bill C-46), police officers no longer need to suspect a person of impaired driving in order to demand a breath test. They can now conduct random mandatory roadside breath tests to screen for alcohol impairment. This means that drivers who are stopped for any other lawful reason, such as a traffic violation, or a check stop, may be required to provide a breath test.

Further changes to the law also allow police officers to demand a breath test for impaired driving up-to two hours after a person has been driving, meaning they do not have to be operating a motor vehicle at the time. Persons who are found impaired within this 2-hour period face new Criminal Code offences with penalties that include mandatory fines and up-to life in prison, depending on the severity of the offence. It is up to the driver to prove they only consumed alcohol after they stopped driving.

Failing a breath test or SFST or refusing to provide a breath or oral sample or perform a SFST can result in serious charges under the Canadian Criminal Code. If you have an injury or illness that prevents you from being able to blow enough air into the screening machine, you may have a valid excuse for refusing.

While it is a criminal offence to refuse to submit to a roadside test, you do not have the right to consult with a lawyer first. If the breath-screening indicates that you have consumed a certain level of alcohol, you can be arrested and taken to the police station (or medical facility) where you may have to perform additional breath screening tests and provide a blood sample taken by a trained medical technician, in order to determine your exact blood-alcohol level for evidentiary purposes. Before taking the breath test and providing the blood sample at the police station, you do have the right to consult with a lawyer.

Drug–impaired driving tests

If a police officer suspects a driver has drugs in their system, they may demand a roadside oral fluid sample and/or conduct a Standardized Field Sobriety Test.

Unlike new alcohol impaired driving laws in which police do not need to suspect alcohol impairment in order to stop a driver, police do need reasonable suspicion that a driver has drugs in his or her system in order to demand a driver take a roadside oral fluid screening test. This could include a driver erratically moving in and out of lanes, or following other vehicles at unsafe distances, as well as physical including red eyes, agitation, muscle tremors or unusual speech patterns.

If the driver fails the SFST or provides a positive oral sample test, they may be arrested and taken to a police station for further tests. This may include a drug recognition evaluation at a police station, providing a blood sample, or additional bodily fluid samples (urine or oral) to confirm previous findings of impairment.

Evaluation for drug impairment includes sobriety tests that are similar to tests for alcohol impairment, as well as taking blood pressure, oral body temperature and pulse, and measuring pupil size in different lighting conditions.

Drivers who fail to comply with these requests, or who comply and are deemed to be under the influence of drugs, may be subject to criminal charges that carry the same penalty as driving while impaired by alcohol.


There are penalties under both the Ontario Highway Traffic Act and the Canadian Criminal Code for impaired driving offences.

Highway Traffic Act

The Ontario government has recently increased the penalties for refusing to take a drug or alcohol screening test, as well as:

  • testing over the legal limit of 0.08
  • a drug recognition evaluator determines you are impaired

Penalties for these offences include: an immediate 90-day roadside licence suspension, a $550 administrative penalty, a $275 licence reinstatement fee, and your vehicle will be impounded for seven days.

Further offences and penalties

There are also increased penalties for other offences such as registering a blood alcohol concentration of between 0.05 and 0.8 and failing a Standardized Field Sobriety Test. Penalties, depending on if it is a first, second or third occurrence could include: a licence suspension, fines, mandatory alcohol education or treatment programs, ignition interlock condition, and a mandatory medical evaluation. In addition, for each time your licence is suspended, you may be subject to a $275 licence reinstatement fee.

Canadian Criminal Code

Although you cannot be charged with an offence for failing a roadside breath test you can be charged under the Criminal Code with several criminal offences such as driving while exceeding the legal blood/alcohol limit, alcohol-impaired driving, drug-impaired driving, dangerous driving, and criminal negligence.

A blood alcohol concentration of more than 0.08 is a serious criminal offence and will result in serious penalties, including fines, licence suspensions, and up-to 10 years in prison.

View Impaired Driving (DUI / DWI) for more information on provincial and Criminal Code alcohol and drug impaired driving offences and penalties.

If you were at fault for an automobile accident while you were impaired, your automobile insurance policy might not cover damage to your vehicle and you may not be eligible to receive certain other benefits, such as income replacement benefits.

If the police ask you to perform a formal breathalyzer test at the police station, it is your right to consult a lawyer and you should consider doing so.

To erase your criminal record, call toll-free 1-866-362-7143 or learn more at All Cleared. It’s easier than you think.

If you have been charged with a criminal offence, and need to hire a criminal defence lawyer, contact our preferred experts:

The Criminal Law Team

Calvin Barry Criminal Lawyers

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