Toronto Drug-Impaired Driving Lawyer: Cannabis and Prescription Drug DUI Defence

Since cannabis was legalized, police across the GTA have put far more effort into detecting drivers who are high. A charge can follow cannabis use, a prescription you have taken for years, or an illegal drug, and the science behind these cases is less settled than the science of breath testing. A drug impaired driving lawyer in Toronto can look closely at how the officer formed an opinion, when and how samples were taken, and whether the results really prove impairment. At DUI Lawyer Toronto, our team defends drug-impaired driving charges across Toronto and the surrounding regions.

What Counts as Drug-Impaired Driving?

Drug-impaired driving covers three different kinds of charges under section 320.14 of the Criminal Code:

• Impaired to any degree by a drug, or by a drug and alcohol together, under section 320.14(1)(a). No specific blood level is needed. The Crown relies on observations, driving evidence and the opinions of officers with drug recognition training.
• A prescribed THC blood concentration within two hours of driving, under section 320.14(1)(c). For cannabis, that is 5 ng/mL or more.
• A combined alcohol and THC concentration, under section 320.14(1)(d): at least 50 mg of alcohol per 100 mL of blood plus at least 2.5 ng/mL of THC.

The first type applies to any drug: cannabis, opioids, sleep aids, anti-anxiety medication, cocaine and others. The blood concentration offences are closely tied to cannabis. Our page on impaired driving explains how the "any degree" standard works in general.

Cannabis DUI in Ontario: The THC Limits

People often ask whether there is a "legal limit" for driving high. For cannabis, the Criminal Code sets these levels, measured in blood within two hours after ceasing to drive:

These numbers are not a safe-driving guide. You can be charged with impairment under section 320.14(1)(a) even at a low THC level if the Crown alleges your driving ability was affected. For a plain-language breakdown, see our article on cannabis impaired driving limits in Ontario.

Driving High on Prescription or Illegal Drugs

A prescription is not a licence to drive impaired. If a medication affects your coordination, reaction time or judgment, driving while taking it can lead to a charge, even when you followed your doctor's instructions.

At the same time, many people take medication every day without any effect on their driving. Tolerance, dosage, timing and underlying medical conditions matter. Signs officers treat as drug impairment, such as pupil size, pulse, muscle tone or unsteady balance, can also be caused by illness, fatigue, injury, anxiety or a condition like diabetes. Medical records and evidence from your own physician can play an important role in the defence.

Cannabis raises its own timing questions. The effects of smoked or vaped cannabis and of edibles can come on and fade at very different rates, and THC can remain detectable in the blood of regular users after they no longer feel any effect. That gap between detection and impairment is why the two types of cannabis charges are defended differently. A blood concentration charge focuses on the number and when it was measured. An impairment charge focuses on how you actually drove and behaved.

Combining substances adds another layer. A small amount of alcohol together with cannabis or a sedating medication can lead police to lay a charge under section 320.14(1)(a), or under the combined alcohol and THC offence, even where neither substance alone would have reached a prohibited level.

How Police Investigate Drug-Impaired Driving

Oral fluid screening at the roadside

Police can use approved drug screening equipment to test a sample of oral fluid, usually taken with a swab. A positive screen can give an officer grounds to take the investigation further. Screening devices detect the presence of a drug; they do not measure impairment.

Drug recognition evaluation (DRE)

An officer may demand that you go to the station for a drug recognition evaluation by a trained drug recognition evaluator. The evaluation is a structured series of physical coordination tests, eye examinations and checks of vital signs, followed by the officer's opinion on whether you are impaired and by which category of drug. If the evaluator believes you are impaired by a drug, police can demand a sample of oral fluid, urine or blood.

Blood demands

Blood samples are the only way to measure THC concentration for the section 320.14(1)(c) and (d) offences. Blood must be taken by a qualified person, and the timing of the sample in relation to driving is critical to the case.

Refusing an oral fluid demand, a drug recognition evaluation or a blood demand without a reasonable excuse is a separate criminal offence. Our page on breath test refusal explains how refusal charges work.

Zero Tolerance for Novice and Young Drivers

Ontario has zero tolerance rules for some drivers. Novice drivers (G1, G2, M1 and M2) and drivers aged 21 and under must have no alcohol and no drugs in their system when driving. A breach leads to a roadside suspension and other provincial consequences, even where there is no criminal charge. Commercial drivers must have zero alcohol. If you hold a graduated licence, our guide to Ontario G2 licence restrictions explains the conditions that apply to you.

Penalties for Drug-Impaired Driving

Apart from the 2 to 5 ng/mL lesser offence, drug-impaired driving carries the same penalties as alcohol-impaired driving:

• First offence: a mandatory minimum $1,000 fine and a driving prohibition of one to three years
• Second offence: a minimum of 30 days in jail and a prohibition of two to ten years
• Third or subsequent offence: a minimum of 120 days in jail and a prohibition of at least three years
• Maximum sentence where no one is hurt: 10 years by indictment, or two years less a day on summary conviction

Ontario also imposes a 90-day Administrative Driver's Licence Suspension and a 7-day vehicle impoundment when a drug recognition evaluation finds impairment. On conviction, the provincial suspension is one year for a first offence, three years for a second and lifetime for a third, along with the Back on Track program and ignition interlock. See our full guide to DUI fines and penalties.

A conviction is a criminal record. It can affect employment, travel to the United States and, for non-citizens, immigration status.

Defences in Drug-Impaired Driving Cases

Every case depends on its evidence, but drug-impaired driving charges often have more room for challenge than alcohol cases.

Reliability of the DRE opinion

A drug recognition evaluation ends with an officer's opinion. We look at whether each step was done properly, whether the evaluator followed the required procedure, whether the results actually point to the drug category alleged, and whether a medical or innocent explanation fits the signs just as well. Evaluation notes and station video are compared line by line.

Timing and handling of samples

The THC offences require a concentration within two hours of driving. Delays in obtaining a blood sample, gaps in the chain of custody, and questions about storage and analysis can all affect whether the result can be relied on. A toxicology report may be needed to interpret the numbers.

Medical explanations

Legitimate medication, chronic conditions, injuries and fatigue can explain many of the signs officers record. Evidence from treating doctors can help put those observations in context.

Charter rights

Police need lawful grounds to detain you and to make each demand (sections 8 and 9 of the Charter), and after arrest you must be told of your right to counsel and given a real chance to use it without delay (section 10(b)). Evidence obtained in breach of these rights may be excluded under section 24(2).

Delay

Under R. v. Jordan, cases in the Ontario Court of Justice should generally be completed within 18 months.

What Should You Do After a Drug-Impaired Driving Charge?

The steps you take in the first days can make a real difference:

1. Write down your timeline. Note what you took, how much and when, when you last ate and slept, and when you started driving.
2. Gather medical information. Keep a copy of any prescriptions, pharmacy labels and the names of your treating doctors.
3. Do not post or talk about the case. Messages to friends and social media posts can be used as evidence.
4. Keep every document police gave you, including your release papers, suspension notice and impound information.
5. Get legal advice before your first court date, especially if you are a novice driver, hold a commercial licence or are not a Canadian citizen.

Our guide on what to do after a DUI charge covers these steps in more detail.

Drug-Impaired Driving Charges Across the GTA

Drug-impaired driving investigations are carried out by the Toronto Police Service and by regional police in Peel, York, Halton and Durham, with the OPP covering the 400-series highways. Charges are usually heard in the Ontario Court of Justice for the region where you were stopped, whether that is downtown Toronto, North York, Etobicoke or Markham. If you have been charged, reach out to our team for a confidential review of your options.