Drug-impaired driving in Ontario is charged under section 320.14 of the Criminal Code. Police first use a roadside oral fluid screening device if drug use is suspected, then a trained Drug Recognition Evaluator (DRE) conducts a 12-step evaluation, and a toxicologist later analyzes a blood sample. Because the process is more subjective than a breathalyzer reading, the DRE's observations and the lab's findings are both open to challenge.
- Drug-impaired driving is charged under section 320.14 of the Criminal Code, separate from the alcohol-based offence.
- Police need a reasonable suspicion of drug use before demanding a roadside oral fluid sample, using a government-approved screening device.
- A positive screening result is not proof of impairment — it only gives police grounds to require further testing, including a Drug Recognition Evaluation.
- A Drug Recognition Evaluator (DRE) conducts a standardized 12-step physical evaluation and can demand a blood, urine, or oral fluid sample for lab analysis.
- Unlike a breathalyzer's simple numerical limit, drug impairment evidence relies on the DRE's observations matching a recognized drug category plus a toxicologist's findings — both of which can be challenged.
- A drug-impaired driving conviction carries the same mandatory driving prohibitions and penalties as an alcohol-based DUI.
What Is Drug-Impaired Driving?
Drug-impaired driving is charged under section 320.14 of the Criminal Code, which makes it an offence to operate (or have care or control of) a motor vehicle while impaired by a drug, by alcohol, or by a combination of the two. The offence applies across Ontario, since it is federal criminal law, not provincial traffic law, and it carries the same criminal consequences as alcohol-based impaired driving.
What makes a drug case different is proof. There is no single, universally accepted number — like a blood-alcohol reading — that cleanly defines impairment for every drug. Instead, the Crown typically has to rely on a combination of roadside screening, a trained officer’s physical evaluation, and laboratory toxicology to build the case.
Roadside Oral Fluid Screening
If an officer has a reasonable suspicion that a driver has a drug in their body, they can demand a sample of oral fluid (saliva) using a government-approved screening device at the roadside. These devices are designed to flag the likely presence of certain drug categories above set cut-off levels.
A positive screening reading does not, by itself, prove impairment. It is a threshold tool that gives police grounds to pursue further investigation — most often a Drug Recognition Evaluation and a demand for a sample to be sent for laboratory analysis.
The Drug Recognition Evaluation (DRE)
Where police suspect impairment by a drug, a specially trained Drug Recognition Evaluator can be called to conduct a standardized, multi-step physical evaluation at the station. This typically includes checks of eye movement and pupil size, muscle tone, pulse and blood pressure, coordination, and a series of physical tests, along with the driver’s own statements about recent drug use.
Based on that evaluation, the DRE forms an opinion about whether the driver is impaired and, if so, which category of drug is likely responsible. The DRE can then demand a blood, urine, or oral fluid sample, which is sent to a laboratory for confirmation.
The DRE’s opinion is a trained but still subjective human judgment, applied in the field under time pressure. Whether the officer followed the standardized protocol correctly, and whether the signs observed genuinely matched the drug category later found in the lab results, are both legitimate areas to examine closely.
How This Differs From Alcohol-Based DUI
An alcohol “over 80” charge is comparatively straightforward to prove: a breathalyzer produces a specific blood-alcohol concentration, and that number does most of the evidentiary work. A drug case is built in layers instead.
| Alcohol DUI | Drug-Impaired Driving |
|---|---|
| Breathalyzer gives a precise numeric reading | No single accepted numeric standard across all drugs |
| Approved Screening Device at roadside | Oral fluid screening device plus a full DRE evaluation |
| Largely objective, instrument-based proof | Combination of a trained opinion and later toxicology |
| One main officer typically involved | Arresting officer, DRE, and a toxicologist often all involved |
This layered process gives a drug-impaired driving case more moving parts — and more potential points to challenge — than a straightforward breathalyzer-based prosecution.
Challenging Toxicologist and DRE Evidence
A drug-impaired driving defence often focuses on the quality and consistency of the evidence at each stage:
- Grounds for the initial demand — whether the officer genuinely had a reasonable suspicion before requiring the roadside sample
- DRE protocol compliance — whether the standardized steps of the evaluation were followed and properly documented
- Consistency between the DRE opinion and the lab results — a mismatch between the drug category the DRE identified and what toxicology later found can undermine the Crown’s case
- Sample handling and chain of custody — how the blood, urine, or oral fluid sample was collected, stored, and tested
- Timing — the gap between driving and sample collection, given how some drugs metabolize
A driver is stopped and shows signs consistent with cannabis impairment on a DRE, but the toxicologist’s report later indicates levels more consistent with past use than recent impairment. That inconsistency between the officer’s opinion and the scientific evidence can become a central issue at trial.
What to Do If You Are Charged
If you are facing a drug-impaired driving charge, the steps you take early matter. Obtain full disclosure, including the DRE’s notes and the toxicology report, as soon as possible. Avoid discussing the circumstances of your arrest with anyone other than your lawyer, and do not assume a screening device result or a DRE opinion automatically means a conviction — both are evidence to be tested, not a verdict.
Beyond the criminal charge, Ontario’s roadside licence suspension and vehicle impoundment rules can apply immediately and separately from the criminal process. Getting legal advice quickly helps address both tracks.
Facing a drug-impaired driving charge in Toronto or anywhere in Ontario? Call our Toronto criminal defence lawyers at 416-274-2222 for a free consultation.
Frequently Asked Questions
Drug-impaired driving is charged under section 320.14 of the Criminal Code, which makes it an offence to operate a motor vehicle while impaired by a drug, by alcohol, or by a combination of the two. It sits alongside, but separate from, the alcohol-specific impaired driving and "over 80" offences.
No. An officer must have a reasonable suspicion that a driver has a drug in their body before demanding a roadside oral fluid sample using an approved screening device. This is a lower threshold than the "reasonable grounds" needed to arrest, but it is not automatic or arbitrary.
Not automatically. A positive screening result only establishes grounds for the officer to require further investigation, which usually means a Drug Recognition Evaluation and a demand for a blood, urine, or oral fluid sample for laboratory analysis. The screening device result alone is not conclusive proof of impairment.
A specially trained police officer conducts a standardized multi-step physical evaluation, checking things like eye movement, muscle tone, pulse, blood pressure, and coordination. The DRE then forms an opinion about whether the driver is impaired and, if so, by which category of drug, which can later be compared against laboratory results.
Alcohol impairment is measured against a fixed blood-alcohol concentration using a breathalyzer, which gives a precise, largely objective number. Drug impairment evidence is more layered: it depends on the DRE's trained observations matching a recognized pattern plus corroborating toxicology, which makes the opinion-based portion of the evidence more open to cross-examination.
Yes, in the right circumstances. Common angles include the lawfulness of the initial screening demand, whether the DRE followed the standardized protocol correctly, whether the DRE's observed signs actually matched the drug category identified, and whether the toxicology results support — or undermine — the DRE's conclusions.
Penalties mirror those for alcohol-based impaired driving, including a mandatory driving prohibition, a criminal record, and escalating consequences for subsequent offences. Ontario's administrative licence suspension and vehicle impoundment regime also applies at the roadside, independent of the criminal process.