What Is an Ignition Interlock Device?
An ignition interlock device is a breathalyzer wired into a vehicle’s ignition system. Before the vehicle will start, the driver must blow into the device and provide an alcohol-free breath sample. If alcohol is detected, the vehicle will not start. The device also requires periodic rolling retests while driving — the driver must provide additional breath samples at random intervals to confirm they have not consumed alcohol after starting the vehicle.
In Ontario, the ignition interlock program is administered by the Ministry of Transportation of Ontario (MTO). The program applies to anyone convicted of an impaired driving offence under the Criminal Code, including impaired operation, over 80, and refusal to provide a breath sample. Participation in the program is mandatory — it is not optional and cannot be waived by the court.
Who Must Use an Ignition Interlock Device?
Every person convicted of an impaired driving offence under sections 320.14 or 320.15 of the Criminal Code must participate in Ontario’s ignition interlock program before having their full driving privileges restored. This applies to:
- First offenders — convicted of impaired driving, over 80, or refusal for the first time
- Second offenders — convicted of a second impaired driving offence
- Third or subsequent offenders — convicted of three or more impaired driving offences
The interlock requirement applies regardless of whether the offence was prosecuted by indictment or summarily, regardless of the BAC reading, and regardless of whether the conviction was for alcohol-impaired or drug-impaired driving.
The interlock requirement does not apply if the impaired driving charge was resolved by a plea to a non-criminal offence such as careless driving under the Highway Traffic Act. This is one of the key advantages of a DUI reduced to careless driving — it avoids both the criminal record and the interlock program.
How Long Does the Interlock Period Last?
The duration of the interlock period depends on the number of prior impaired driving convictions. The interlock period runs after the Criminal Code driving prohibition has ended, meaning the total time before a full, unrestricted licence is the prohibition period plus the interlock period.
| Conviction | Mandatory Min. Penalty | Driving Prohibition | Interlock Period | Total to Full Licence |
|---|---|---|---|---|
| First offence | $1,000 fine | Min. 1 year | 1 year | Min. 2 years |
| Second offence | 30 days jail | Min. 2 years | 3 years | Min. 5 years |
| Third or subsequent | 120 days jail | Min. 3 years | 6 years | Min. 9 years |
These are minimum periods. The court may impose a longer driving prohibition than the minimum, which would extend the total time before full licence reinstatement. The interlock period itself is set by Ontario regulation and is not increased by the court — but violations during the interlock period can extend it.
Cost of the Ignition Interlock Program
All costs of the ignition interlock program are borne by the convicted person. The program involves several categories of expense:
Installation. The interlock device must be installed by an approved service provider. Installation fees typically range from $150 to $200. The device is installed in the vehicle’s ignition system and connected to the vehicle’s electrical system.
Monthly lease and monitoring. The interlock device is leased from the service provider at a monthly fee, typically between $100 and $150. This fee covers the device, data downloads at service visits, and reporting to the MTO. For a first offence with a one-year interlock period, monthly fees alone total $1,200 to $1,800.
Service visits. The device must be serviced and calibrated at regular intervals — typically every 30 to 60 days. Service visits are included in the monthly fee with most providers, but missed appointments may result in additional charges.
Removal. At the end of the interlock period, the device is removed by the service provider. Removal fees are typically $50 to $100.
Total cost. For a first offence (one-year interlock), the total cost is typically $1,500 to $2,500. For a second offence (three-year interlock), the total cost can exceed $5,000. For a third offence (six-year interlock), the cost can reach $10,000 or more. These costs are in addition to fines, the Back on Track program fee, licence reinstatement fees, and increased insurance premiums.
How the Device Works
The ignition interlock device requires the driver to provide a breath sample before starting the vehicle. The driver blows into a mouthpiece attached to the device for several seconds. If the sample is alcohol-free — below the device’s set threshold, which is near zero — the vehicle will start normally. If alcohol is detected, the vehicle will not start and the driver must wait a lockout period (typically several minutes) before trying again.
Rolling retests. While the vehicle is in operation, the device requires additional breath samples at random intervals. The driver is given a warning signal and a window of time to provide the sample. If the driver fails to provide a sample or if the sample contains alcohol, the device logs the event and activates a warning — typically by sounding the horn and flashing the lights until the vehicle is turned off. The device does not shut off the engine while the vehicle is in motion.
Data logging. Every breath sample — pass or fail — is recorded by the device along with the date, time, and BAC reading. This data is downloaded at each service visit and reported to the MTO. The data record provides a complete history of the driver’s alcohol use during the interlock period.
Temperature and tampering. The device includes sensors to detect attempts to circumvent the breath test, such as using compressed air or another person’s breath. Tampering with or disconnecting the interlock device is an offence that can result in further suspension of driving privileges and criminal charges.
Violations and Consequences
The interlock program requires strict compliance. Violations during the interlock period can result in significant consequences:
Failed breath tests. A pattern of failed breath tests — even if the vehicle was not started — is reported to the MTO and may result in an extension of the interlock period or removal from the program. A single failed test may not trigger consequences, but repeated failures indicate ongoing alcohol use.
Missed service appointments. The device must be serviced at regular intervals. Failing to attend a scheduled service appointment results in the device entering a lockout mode — the vehicle will not start until the device is serviced. Chronic missed appointments can lead to licence suspension.
Tampering. Any attempt to tamper with, disconnect, or circumvent the device is a serious violation. Tampering is detected by the device’s sensors and reported to the MTO. Consequences include immediate licence suspension, extension of the interlock period, and potential criminal charges.
Driving without interlock. Operating a motor vehicle that is not equipped with an ignition interlock device while subject to an interlock condition is an offence under the Highway Traffic Act. This can result in further licence suspension, fines, and an extension of the interlock requirement.
Early Exit From the Program
Ontario’s ignition interlock program does not generally allow early exit. The interlock period prescribed for each offence level must be completed in full. There is no provision for applying to have the interlock removed before the prescribed period expires based on good behaviour or compliance.
However, the converse is also true — violations can extend the interlock period beyond the standard term. A person who completes the interlock period without violations and meets all other reinstatement requirements (including completion of the Back on Track program and payment of all applicable fees) will be eligible for a full, unrestricted licence at the end of the prescribed period.
The Back on Track Program
Ontario’s Back on Track program is a separate requirement that runs alongside the interlock program. Completion of Back on Track is mandatory before a convicted impaired driver can have their licence reinstated.
The program is administered by the Centre for Addiction and Mental Health (CAMH) and involves:
- An assessment of the convicted person’s relationship with alcohol and/or drugs
- An education workshop covering the effects of alcohol and drugs on driving ability
- A follow-up assessment to determine whether additional treatment is recommended
If the follow-up assessment determines that the person has a substance use issue, they may be required to complete a treatment program before being eligible for licence reinstatement. The treatment program adds time and cost to the reinstatement process.
The Back on Track program has its own fees, which are separate from the interlock costs. The program must be completed within a prescribed timeframe — failure to complete it on time can delay licence reinstatement.
Getting Your Full Licence Back
Regaining a full, unrestricted driver’s licence after a DUI conviction requires completing several steps in sequence:
1. Serve the driving prohibition. The Criminal Code driving prohibition must expire. This is a minimum of one year for a first offence, two years for a second, and three years for a third or subsequent offence under section 320.24 of the Criminal Code.
2. Complete the Back on Track program. The assessment, education, and any required treatment components must be completed and the completion certificate submitted to the MTO.
3. Install the interlock device. Once the driving prohibition has ended and Back on Track is underway, the convicted person can apply for a licence with an interlock condition. The interlock device must be installed before the restricted licence is issued.
4. Complete the interlock period. Drive with the interlock device for the prescribed period without violations.
5. Pay reinstatement fees. The MTO charges a licence reinstatement fee. All outstanding fines, fees, and costs must be paid before the full licence is issued.
6. Full licence issued. After all requirements are met, the MTO issues a full, unrestricted licence. For a first offence, the earliest this can happen is approximately two years after conviction. For a second offence, the earliest is approximately five years.
How a DUI Lawyer Can Help
The most effective way to avoid the ignition interlock program is to avoid a Criminal Code conviction. Defence counsel can challenge the impaired driving charge itself — targeting Charter violations, breath instrument reliability, procedural failures, and weaknesses in the Crown’s evidence. If the charge is withdrawn or the accused is acquitted, the interlock program does not apply.
Where a full withdrawal is not achievable, negotiating a resolution to careless driving under the Highway Traffic Act avoids the interlock requirement entirely. Careless driving is a provincial offence — it does not result in a criminal record, mandatory minimum penalties, or participation in the interlock program. For more on this outcome, see our guide on DUI reduced to careless driving.
Even where a conviction is the likely outcome, defence counsel can affect the length of the driving prohibition imposed by the court. The longer the prohibition, the longer the total period before full licence reinstatement. Effective sentencing submissions can keep the prohibition at or near the mandatory minimum.
For a comprehensive overview of DUI charges and DUI penalties in Ontario, including the mandatory minimums and driving prohibitions for each offence level, see our related guides. If you are facing a first DUI charge, understanding the full consequences — including the interlock program — is essential to making informed decisions about your defence.