To beat an “Over 80” impaired driving charge in London, your lawyer can challenge the accuracy of the breathalyzer machines. This involves demanding the device’s calibration logs through court disclosure and proving that the London Police Service officer either failed to maintain the machine properly or made procedural errors during your test.
When the London Police pull you over and demand a breath sample, the results of that Approved Screening Device (ASD) can instantly lead to your arrest. Later, at the police station, a larger machine called an Intoxilyzer will measure your precise blood alcohol concentration. Many drivers mistakenly believe that if the machine says “Fail” or prints a number over the legal limit, they are automatically guilty. This is a myth.
Breathalyzers are highly sensitive machines, and like all machines, they require rigorous maintenance, calibration, and human operation to function correctly. ⚔️ If an officer makes a mistake, or if the device has a history of technical errors, the readings cannot be legally trusted in the Ontario Court of Justice. To mount a highly technical defence, you need to hire a seasoned criminal defence lawyer from our directory who knows how to dissect police testing procedures.
Step-by-Step Process in London, Ontario
Challenging a machine’s accuracy is a methodical process that heavily relies on science and cross-examination at the Dundas Street courthouse. Here is how your defence team will attack the evidence.
Step 1: Requesting Comprehensive Disclosure
Your lawyer will not just accept the final printed breathalyzer ticket. 📄 They will file a request to the Crown Attorney for comprehensive disclosure. This includes the specific maintenance logs for the exact machine used in your arrest, the calibration records from the weeks prior, and the certificates proving the testing solution used by the London Police was not expired.
Step 2: Scrutinizing the Observation Period
By law, police officers are supposed to observe you for at least 15 minutes before administering a breath test. This is to ensure you do not burp, regurgitate, or use mouthwash, which can leave “mouth alcohol” in your throat and cause the machine to register a falsely high reading. Your lawyer will review police dash-cam and station-cam footage to prove the officer rushed the test and ignored this crucial waiting period.
Step 3: Checking the Technician’s Qualifications
Not every police officer is legally allowed to operate the large evidential breath machines at the police station. 👮♂️ The test must be administered by a “Qualified Technician.” Your lawyer will verify if the officer’s certification was up to date and if they followed the strict operational manual provided by the machine’s manufacturer.
Step 4: Filing a Charter Application
If your lawyer finds that the machine was faulty, or the officer lacked grounds to demand the test in the first place, they will file a Charter Application. They will argue before the judge that your Section 8 rights (protection against unreasonable search and seizure) were violated. If the judge agrees, the breath test results will be excluded from the trial, which usually results in the “Over 80” charge being completely dropped.
How Much Does it Cost in London?
Mounting a technical defence against breathalyzer evidence requires specialized knowledge and often external experts. 💵 Here is what you can expect to spend as of April 2026.
| Expense Type | Estimated Cost (CAD) | Description |
|---|---|---|
| Trial Defence Lawyer | $5,000 – $12,000+ | The flat fee to prepare Charter arguments and cross-examine police technicians at trial. |
| Toxicology Expert Witness | $2,000 – $5,000 | Hiring an independent forensic toxicologist to testify about machine errors or mouth alcohol. |
| Court Transcript Fees | $100 – $300 | Administrative fees to order official transcripts if there are multiple hearings. |
How Long Does the Process Take?
Challenging technical evidence extends the lifespan of a criminal case. 🕐 Waiting for the London Police Service to provide the full calibration logs and maintenance records can easily take 3 to 5 months. If your lawyer needs to consult with a toxicologist and schedule a multi-day trial, the entire process can take 10 to 18 months to reach a final verdict. During this time, you will still be subject to your initial 90-day administrative licence suspension.
Frequently Asked Questions (FAQ)
What happens if the roadside device wasn’t calibrated?
If your lawyer can prove the Approved Screening Device (ASD) used at the roadside was overdue for calibration, it can invalidate the officer’s legal grounds to arrest you and demand the second, more accurate test at the police station. This can cause the entire case to collapse.
Can chewing gum affect the breathalyzer?
Yes, but usually in your favour or to the machine’s detriment. Certain gums, candies, or burping can introduce foreign substances into the machine, which is why the 15-minute observation period is legally required. If an officer tests you with gum in your mouth, the test may be invalid.
Why not just refuse the test if the machine is flawed?
Never refuse a test. Refusing to provide a breath sample is a separate criminal offence under the Criminal Code that carries the same, or even harsher, penalties than failing the test. It is much easier for a lawyer to fight a flawed machine reading than a flat-out refusal.
Will the Crown drop the charge if one log is missing?
Not necessarily. The Crown Attorney will argue that minor paperwork errors do not invalidate the scientific results. Your lawyer must aggressively prove that the missing logs raise a “reasonable doubt” about the machine’s actual functioning at the exact moment you blew into it.
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