Yes, someone else can drive a car equipped with an ignition interlock device (IID), but they are subject to the exact same rules as the primary offender. Any person who drives the vehicle must blow a clean, alcohol-free sample into the IID to start the car and pass random rolling retests while the engine is running. The legal responsibility, however, ultimately falls on the registered owner of the vehicle, who is typically the person required by court or DMV order to have the device installed. If a secondary driver fails a test, it is the primary offender who will face potential penalties, including an extension of the IID requirement.
The core principle is that the interlock is assigned to the vehicle, not a specific driver. This is a critical distinction. The device cannot differentiate between users; it only measures the breath alcohol concentration (BrAC) from whoever provides the sample. Therefore, allowing another person to drive your interlock-equipped car comes with significant risk.
Key Considerations Before Letting Someone Else Drive:
- Court/DMV Order Review: First, you must carefully review the specific terms of your interlock order. Some states or judges may explicitly prohibit anyone else from driving the vehicle. Violating this term could result in serious consequences.
- Absolute Sobriety: You must be 100% confident that any potential secondary driver understands the rules and will remain completely sober before and during driving. There is zero tolerance for alcohol. This includes being cautious about mouthwash, certain medications, or foods that could contain trace amounts of alcohol and trigger a violation.
- Understanding Violation Consequences: A violation—whether a failed start-up test or a missed rolling retest—is logged by the device. During your regular calibration appointment (usually every 30-60 days), these logs are downloaded and reported to the monitoring authority. A violation caused by your friend or family member will be treated as your violation.
The following table outlines the general stance of various state monitoring authorities, though you must verify with your specific jurisdiction.
| State Example | Typical Policy on Other Drivers | Primary Risk for the Registered Owner |
|---|
| California | Generally permitted, but the offender is responsible for all violations. | High. Any violation extends the IID restriction period. |
| Texas | Allowed, but the offender must be present in the vehicle. | Extreme. Violations can lead to license revocation. |
| Florida | Permitted if the other driver is sober and licensed. | Moderate to High. Violations are recorded and reviewed. |
| New York | Allowed, but the order should be checked for restrictions. | High. Multiple violations can result in program removal and harsher penalties. |
| Arizona | Strictly prohibited in many cases by the court order. | Severe. Allowing an unauthorized driver is a separate violation. |
In summary, while it is technically possible, the risks involved in allowing another person to drive your interlock-equipped car are substantial. It requires immense trust and a clear understanding that you are legally accountable for their actions behind the wheel.
