Everything You Need to Know About Interlock Devices

Driving under the influence of alcohol is one of the leading causes of road accidents worldwide. To help prevent impaired driving and promote road safety, many authorities have introduced the interlock device—a smart technological solution that ensures only sober drivers can operate a vehicle.

If you’ve recently been required to install an interlock device, or you simply want to understand how it works, this comprehensive guide will explain everything you need to know: how the system functions, who needs it, and why it’s an essential step toward safer driving and legal compliance.

What Is an Interlock Device?

An interlock device, often referred to as an alcohol interlock, is a small, breath-testing system connected to your vehicle’s ignition. Before you can start the engine, you must provide a breath sample into the interlock device. If the device detects alcohol above a pre-set limit, it prevents the vehicle from starting.

The primary goal of the interlock device is to prevent drink driving by ensuring that the person behind the wheel is sober. These devices are highly reliable and are often mandated by courts or transport authorities like VicRoads for drivers with previous drink-driving offences.

How Does an Interlock Device Work?

The operation of an interlock device is simple but highly effective. Here’s a step-by-step overview:

1. Blow into the Device: Before starting your car, you’ll need to blow into the interlock device mouthpiece.
   

2. Sample Analysis: The device uses advanced fuel cell technology to measure the alcohol content in your breath.
   

3. Result Display: If no alcohol is detected, the engine will start. If alcohol is present, the vehicle remains immobilised.
   

4. Rolling Retests: During long drives, the interlock device may request random retests to ensure you remain alcohol-free while driving.
   

5. Data Logging: Every test result—pass, fail, or missed—is stored in the device’s memory for review during service appointments.
   

The data collected from your interlock device is securely stored and transmitted to the relevant authority, ensuring transparency and accountability.

Who Needs an Interlock Device?

The installation of an interlock device is typically required for drivers who have been convicted of drink-driving offences. However, there are other situations where it may be used voluntarily or as part of company safety policies.

You may be required to install an interlock device if:

• You’ve been caught driving with a blood alcohol concentration (BAC) over the legal limit.

• You’ve refused to undergo a breath test when requested by police.

• You’re a repeat drink-driving offender.

• You are reinstating your licence after a court-imposed suspension.
  

Fleet owners and businesses may also install interlock devices in company vehicles to promote safety and reduce liability risks.

Benefits of Using an Interlock Device

Installing an interlock device offers several key benefits for individuals, families, and communities.

1. Promotes Safer Roads: The interlock device prevents drunk drivers from starting their vehicles, reducing accidents and fatalities.
   

2. Encourages Responsible Behaviour: It serves as a reminder to avoid alcohol consumption before driving.
   

3. Restores Driving Privileges: For those under a court order, compliance with an interlock device program can help regain their licence sooner.
   

4. Ensures Legal Compliance: The device provides accurate records of breath tests, helping you meet authority or court requirements.
   

5. Protects Others: Keeps passengers, pedestrians, and other road users safe by preventing impaired driving incidents.
   

By promoting accountability and safe driving practices, an interlock device plays an essential role in building a responsible driving culture.

Installation Process of an Interlock Device

Installing an interlock device is a straightforward process handled by licensed professionals. Here’s what typically happens:

1. Book an Appointment: Contact an accredited service provider for installation.
   

2. Installation: The technician will connect the interlock device to your vehicle’s ignition system.
   

3. Training: You’ll receive hands-on training on how to use and maintain the device properly.
   

4. Regular Servicing: You must return periodically for servicing and data downloads (usually every 30–60 days).
   

5. Program Completion: After meeting your program requirements, the interlock device will be removed once approved by the relevant authority.
   

Professional installation ensures your interlock device functions correctly and that your compliance data is recorded accurately.

Maintenance and Monitoring

Every interlock device must undergo regular maintenance to ensure accuracy and performance. During servicing appointments, your provider will:

• Calibrate the interlock device for accuracy.

• Download and review stored data.

• Replace mouthpieces and inspect the system.

• Send reports to VicRoads or your local authority.
  

Tampering with an interlock device or failing to attend scheduled services can result in penalties, program extensions, or legal action.

Legal Compliance and Reporting

An interlock device is not just a safety tool—it’s also a legal requirement for many drivers. The data collected during your program period is reviewed by authorities to determine your eligibility for licence reinstatement.

To stay compliant, you must:

• Attend all service appointments on time.

• Avoid tampering with or bypassing the device.

• Provide clean breath samples consistently.

• Follow all program guidelines issued by VicRoads or your local authority.
  

Failure to comply can result in your interlock period being extended or your licence application being delayed.

Choosing the Right Interlock Device Provider

When selecting a service provider, choose one that is certified, reputable, and experienced in installing interlock devices. Look for:

• VicRoads accreditation (or local authority certification)

• Transparent pricing and terms

• Convenient service locations

• Excellent customer support
  

A reliable provider will ensure that your interlock device is properly installed, maintained, and serviced throughout the duration of your program.

Conclusion

The interlock device is a proven and effective tool for promoting safe and responsible driving. Whether you are required to install one as part of a court order or you choose to use it voluntarily, this system ensures that only alcohol-free drivers are behind the wheel.

By complying with your program and maintaining your interlock device properly, you take a crucial step toward restoring your driving privileges, protecting others on the road, and building a safer community for everyone.