Calgary Impaired Driving & DUI Defence Lawyer

Operating a vehicle while under the influence of alcohol, drugs, or both impairs your ability to drive. Police establish impairment through observations such as erratic driving patterns, slurred speech, bloodshot eyes, poor coordination, and performance on Standardized Field Sobriety Tests (SFSTs). The Crown does not need to prove a specific BAC level — impairment to any degree is sufficient for conviction.

Operating a vehicle with a blood alcohol concentration (BAC) at or above 80 milligrams of alcohol per 100 millilitres of blood within two hours of driving. This is proven through breathalyzer readings from an approved instrument, not through observable impairment — meaning you can be charged even if you appeared to drive normally. An impaired driving lawyer in Calgary challenges over 80 charges by examining instrument calibration, operator qualifications, and the timing between samples.

Operating a vehicle with a blood drug concentration at or exceeding prescribed limits. For THC (cannabis), the Criminal Code sets two thresholds: 2 nanograms per millilitre of blood as a less serious offence, and 5 nanograms or more as a full criminal offence equivalent to alcohol impairment. Drug Recognition Expert (DRE) evaluations and oral fluid screening devices are used at the roadside. Since cannabis legalization, drug-impaired driving charges in Calgary have increased significantly. Centobin Law also defends clients facing drug offence charges involving possession and trafficking.

Refusing or failing to comply with a lawful police demand to provide a breath, blood, or oral fluid sample — or to perform a physical sobriety test — without a reasonable excuse. Under Section 320.15(1), refusal carries the same penalties as a conviction for impaired driving itself. This is a standalone criminal offence and applies even if the person was not actually impaired.

Police must have a lawful reason to stop your vehicle. Random stops at check stops are permitted under the Alberta Traffic Safety Act. Still, an officer who pulls you over outside a checkstop must articulate a specific reason — such as a traffic violation, erratic driving, or equipment deficiency. If the initial stop was arbitrary or unlawful, all evidence gathered afterward may be excluded. A DUI lawyer in Calgary reviews dashcam footage, dispatch records, and officer testimony to assess whether the stop met the legal threshold.

Before demanding a breath sample on an approved instrument (breathalyzer), the officer must have reasonable and probable grounds to believe an impaired driving offence has been committed. This requires both a subjective belief and objective evidence supporting that belief. An impaired driving lawyer in Calgary scrutinizes the officer’s notes, in-car camera footage, and testimony to determine whether the grounds were genuinely formed and articulable — or whether they were manufactured after the fact.

Approved instruments must be properly calibrated, maintained, and operated by a qualified technician. A criminal defence lawyer in Calgary reviews calibration check results, error messages, the timing between samples, and whether the instrument was operated according to the manufacturer’s specifications and the Canadian Society of Forensic Science standards. If the instrument malfunctioned or the technician deviated from proper procedure, the breath readings may be unreliable and subject to exclusion.

Under Section 10(b) of the Charter, you have the right to speak with a lawyer without delay upon arrest or detention. Police must inform you of this right, provide you with a reasonable opportunity to contact counsel in private, and refrain from questioning or eliciting evidence until you have exercised that right. Failure to provide timely and adequate access to counsel can result in the exclusion of all evidence obtained after the breach — including the breath samples themselves.

In cases where the charge is impaired operation (rather than over 80), the Crown relies heavily on the officer’s observations — driving pattern, physical appearance, coordination, and performance on field sobriety tests. A DUI defence lawyer in Calgary challenges these observations by presenting alternative explanations (fatigue, medical conditions, nervousness, environmental factors), examining the officer’s training and experience, and testing the reliability of their notes against dashcam and body-worn camera footage.

If the breathalyzer results show a BAC over 80 mg, the defence can present evidence showing that the accused’s actual consumption of alcohol was inconsistent with the breathalyzer reading. This requires credible evidence of what was consumed and expert toxicology testimony calculating the BAC based on that consumption pattern. If the evidence raises a reasonable doubt about the accuracy of the readings, the presumption created by the breath results can be rebutted.

Every accused person has the right to be tried within a reasonable time. Under the framework established by the Supreme Court of Canada, delays beyond established ceilings (18 months in Provincial Court, 30 months in Court of King’s Bench) are presumed unreasonable. If the Crown cannot justify the delay, the charges may be stayed permanently — regardless of the strength of the evidence. An impaired driving lawyer in Calgary monitors timelines from the date of charge to ensure this right is protected.

An impaired driving conviction creates a federal criminal record visible on background checks conducted by employers, landlords, and border agencies. A record suspension (formerly a pardon) cannot be applied for until 5 years after all sentences, fines, and conditions are fully completed. During that period, the record remains active and searchable.

Many employers in Calgary and across Alberta conduct criminal background checks as a condition of hiring. Positions requiring driving, security clearance, government access, or professional licensing may become inaccessible. An impaired driving conviction can disqualify candidates in transportation, oil and gas, healthcare, education, and financial services. Learn more about how a criminal conviction affects employment.

A criminal record for impaired driving can result in denial of entry to the United States and other countries that screen for criminal history. U.S. Customs and Border Protection has access to Canadian criminal records through shared law enforcement databases. Even a single DUI conviction can result in being turned away at the border without a U.S. Entry Waiver (Form I-192 or I-212).

For non-citizens, an impaired driving conviction can trigger inadmissibility proceedings, affect pending immigration applications, and, in serious cases, lead to a removal order. The intersection between criminal charges and immigration status requires immediate legal attention from impaired driving defence counsel in Calgary who understands both systems.

A DUI conviction in Alberta results in classification as a high-risk driver. Insurance premiums typically increase by 200% to 300% above standard rates and remain elevated for 6 to 10 years. Some insurers refuse coverage entirely, requiring drivers to obtain insurance through Alberta’s Facility Association at premium rates that can exceed $5,000 per year.

After a criminal conviction, Alberta requires participation in the Ignition Interlock Program before full driving privileges are restored. The device must be installed at your expense in every vehicle you operate. For a first offence, the interlock period is 1 year; for a second offence, 3 years; and for a third or subsequent offence, 5 years.