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

Region: Ontario Answer # 771

Three roadside tests for impairment

The police do not have to suspect that a driver is impaired before they stop a vehicle. In fact, the police have the legal right to conduct random spot checks for impaired drivers. 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 or drugs, and they will likely require you to undergo a roadside test or provide a roadside sample. This area of the law is dealt with primarily in section 320 of the Criminal Code.

If you have been charged with a criminal offence such as impaired driving, it is important to hire an experienced criminal defence lawyer as soon as possible.

The three roadside tests are:

  1. Standard Field Sobriety Test (SFST), for alcohol or drug impairment,
  2. Breath test for impairment due to alcohol, and
  3. Oral fluid (saliva) test for impairment due to drugs.


The police may ask you to get out of your car to perform a Standardized Field Sobriety Test (SFST). A SFST allows police officers to examine the eyes of drivers, as well as to put drivers through a series of physical tests, including having them:

  • walk in a straight line,
  • stand and turn, or
  • stand on one leg.

2. Breath test for impairment by alcohol

To test a driver’s alcohol consumption, the police have the legal right to administer a breath-screening test at the side of the road after someone has been pulled over. The roadside breath-screening test helps the police determine the amount of alcohol per 100 ml of blood in a person’s body. The breath test is done using an Approved Screening Device (ASD) such as a breathalyzer, which provides a reading of the blood alcohol level.

Mandatory alcohol breath screening tests

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. A reasonable suspicion may have arisen due to observations by the police, such as the driver’s appearance, physical movements, whether the driver or the car smelled of alcohol, as well as how the driver answered questions.

Under recent changes to the Criminal Code, section 320.27(2), 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 other reasons, such as traffic violations, or a random check stops, may be required to provide a breath test.

Three-hour limit for conducting a breath test:

Under section 320.27(1) of the Criminal Code police officers are allowed to demand a breath test for anyone who has operated a motor vehicle within three hours of the test.

80 mg or over within two-hours of driving:

The three-hour breath testing time-limit is not to be confused with the new impaired driving laws (section 320.14), which include anyone who “has, within two hours after ceasing to operate a motor vehicle, a blood alcohol concentration that is equal to or exceeds 80 mg of alcohol in 100 mL of blood”.

3. Oral fluid (saliva) sample for impairment by drugs

In contrast to the mandatory breath screening test, police do need to have a reasonable grounds to suspect that a driver has drugs in his or her system in order to demand that a driver take a roadside oral fluid screening test.

A reasonable grounds to suspect could include a driver:

  • erratically moving in and out of lanes,
  • following other vehicles at unsafe distances,
  • having red eyes, muscle tremors or unusual speech patterns, etc.

Three-hour limit for bodily substance sample:

Under section 320.27(1) of the Criminal Code, police officers are allowed to demand bodily fluid testing for anyone who has operated a motor vehicle within three hours of the test. This includes oral fluid (saliva) testing at the roadside.

Blood drug concentration over the legal limit within two-hours of driving:

Again, the three-hour time-limit for obtaining a bodily substance sample is not to be confused with the offence of impaired driving (section 320.14), which includes anyone who “has, within two hours after ceasing to operate a motor vehicle, a blood drug concentration that is equal to or exceeds the blood drug concentration for the drug that is prescribed by regulation.” Refer to the Blood Drug Concentration Regulations to view the limits.

For more information on cannabis-impaired driving, refer to our Cannabis Law and Driving section.

Failing or refusing a roadside test

Failing a test:

Failing one or more of the roadside tests SFST, breath test, or oral fluid test— can result in being charged under the Criminal Code. If the driver fails any of these roadside tests, they may be arrested and taken to a police station or medical facility for further testing. However, before taking further tests and or providing samples at the police station, you do have the right to consult with a lawyer.

Refusing a test:

It is important to note that you do not have the right to consult with a lawyer before providing these roadside tests. Furthermore, it is a criminal offence under Criminal Code section 320.15(1) to refuse to provide a roadside SFST, breath test, or oral fluid sample. However, if you have a reasonable excuse, such as an injury or illness that prevents you from being able to blow enough air into the breathalyzer screening machine, you may have a valid excuse for refusing.

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

Get Help

If you have a criminal record and want to erase it, call toll-free 1-888-808-3628 or learn more at Pardon Partners. It’s easier than you think.

If you have been charged with a criminal offence, contact our preferred criminal defence expert, Calvin Barry Criminal Lawyers.

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