RGZLegal Impaired Driving Defenses

There are many technicalities that exist in and around impaired driving charges. Very specific procedures must be followed by police officers before conducting a traffic stop and prior to making an arrest. These procedures are set out in the Criminal Code of Canada.

If these procedures are not followed, a testimony by a police officer stating that a driver was impaired will not be admitted as evidence in your impaired driving case. In addition, officers must establish that they have ‘reasonable grounds’ to charge someone. They must prove that they had substantial reason to believe that the driver’s ability to operate a vehicle was impaired by drugs or alcohol.

Police officers must be able to identify multiple factors upon which their suspicions of impaired driving are founded. If they are unable to do so, there may be a defense to the charge.

Here are a few of the most common defenses used in impaired driving cases:

Reasonable and Probable Grounds

In an impaired driving case, police must cite a specific reason to make a routine traffic stop and question an individual about their drinking habits. This reason is commonly known as establishing “reasonable and probable grounds”.

If an office does not establish “reasonable and probable grounds,” the evidence provided in support of an impaired driving case will not be accepted.

Rights to Counsel

In any potential criminal case, police are responsible for informing you of your right to speak to a lawyer. By law, officers must make you aware of this right before they begin interrogating you.

As an individual, you should be aware that you have the right to counsel, that police are required to notify you of this right promptly, and that you should be given an opportunity to speak with the lawyer of your choice in private.

Recent Driving

You should speak to your lawyer about the last time that you consumed an alcoholic beverage.

In some cases, if your last drink was actually consumed after you drove, being impaired while you were arrested may not necessarily mean that you were driving while impaired.

The Crown Can’t Prove Impaired

As in most criminal cases, The Crown must prove, beyond a reasonable doubt, that an offense has been committed. The officers involved in your case must be able to testify as to the existence of many observed signs of impairment.

Without the establishment of proof, beyond a reasonable doubt, that either alcohol or drugs impaired your ability to operate a vehicle, the judge will be unable to convict you.


Individuals should be aware that they have a right to a trial within a reasonable time limit. If your trial is delayed more than ten months from the date that you were charged, the Crown and Court are responsible. Excluding the time needed to prepare your case, this may create an adequate defense to your charge.