Tennessee Ignition Interlock — Requirements & Costs
When interlock may be required and practical steps.
When Tennessee requires an IID §55-10-409
mandatory when restricted license is granted if BAC ≥ 0.08, minor under 18 in vehicle, or accident resulting from intoxication; discretionary in other first-offense situations.
How long the IID must remain installed
the required interlock usage period is set by statute and can run longer than the restricted-license period; removal is compliance-based, and violations can extend or restart the period — confirm the current requirement with a lawyer.
How the device works in practice
Violations and extensions
Common violations that can extend the IID period or trigger additional consequences:
- Failed startup tests (BAC above threshold)
- Failed rolling retests
- Missed calibration appointments
- Tampering with or attempting to circumvent the device
- Operating a vehicle without an IID when one is required
Costs
IID costs are borne by the offender and include:
- Installation fee
- Monthly monitoring/rental fee
- Removal fee
- Calibration fees (may be included in monthly rental or charged separately)
The IID as a path back to driving
While the IID is a restriction, it is also the mechanism that allows many offenders to resume driving sooner than they would under a full suspension. In Tennessee, Restricted license available under §55-10-409 with IID and/or geographic restrictions. Complying fully with IID requirements — no violations, on-time calibration — is the fastest path to full reinstatement.
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Frequently Asked Questions
General answers to common questions. Specific outcomes depend on your facts and timing.
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