Illinois DUI Defense Guide
MDDP & Ignition Interlock Guide
Keep driving during your DUI suspension. The MDDP program lets you maintain your life while your case moves through court.
You Can Still Drive—Here's How
One of the biggest fears after a DUI arrest is losing the ability to drive. How do you get to work? Take your kids to school? Handle daily life? The good news: Illinois's MDDP (Monitoring Device Driving Permit) program allows most DUI offenders to continue driving throughout their suspension—with an ignition interlock device installed.
The MDDP permits unlimited driving. Not just to and from work. Anywhere, anytime. The only requirement is that you breathe into the device before starting your vehicle and during periodic retests while driving. After helping 3,000+ clients navigate the DUI process, Andy Sotiropoulos guides every client through MDDP eligibility and installation as part of the defense strategy.
90-Day Deadline: While you prepare for MDDP, don't forget the separate 90-day deadline to challenge your license suspension. These are two different processes that run simultaneously. Learn about the 90-day deadline →
MDDP Eligibility
Most first-time DUI offenders are eligible for an MDDP. You qualify if:
- You're serving a statutory summary suspension for DUI (first or subsequent)
- You have not been convicted of DUI previously (supervision counts differently)
- You agree to install and maintain an approved ignition interlock device
- You pay the $30 MDDP permit fee
For second or subsequent offenders, MDDP may still be available, but requirements and restrictions are more complex. Andy can assess your specific eligibility based on your driving record and case details.
How the Ignition Interlock Device Works
The ignition interlock device (IID) is a small breathalyzer unit installed in your vehicle's dashboard, wired to the ignition system:
- Start-up test: Before the engine starts, you breathe into the device. If your BAC is below the preset limit (typically .025), the vehicle starts normally.
- Rolling retests: While driving, the device prompts random retests every 15-45 minutes. You have several minutes to provide a sample. The engine does NOT shut off if you fail—but the horn honks and lights flash until you safely pull over.
- Data recording: Every test result, skip, and violation is logged and transmitted to the monitoring company and Secretary of State.
- Camera equipped: Most devices include a camera to verify the registered driver is providing the breath sample.
Installation & Costs
- Installation fee: $30-$100 (one-time)
- Monthly lease & monitoring: $70-$150/month
- Calibration visits: Required every 60-90 days (usually included in monthly fee)
- Removal fee: $30-$50
- MDDP permit fee: $30 (paid to Secretary of State)
- Total estimated cost (6-month suspension): $500-$1,000
The device must be installed on every vehicle you drive. If you share a vehicle with a family member, they'll need to use the device too—though their tests won't be held against your record.
Approved Providers in Illinois
Illinois maintains a list of approved ignition interlock providers. Major providers serving the DuPage and Will County area include Smart Start, Intoxalock, and LifeSafer. Andy can recommend providers based on their reliability, customer service, and proximity to your location.
Schedule installation before your suspension begins so there's no gap in your ability to drive. Your attorney can help you time everything properly.
Compliance Tips
- Don't use mouthwash before driving. Alcohol-based mouthwash can cause false positives. Switch to alcohol-free brands.
- Wait after eating. Some foods (bread, ripe fruit) can ferment and produce trace alcohol readings. Wait 15 minutes after eating before testing.
- Never skip a retest. A missed rolling retest is logged as a violation, same as a failure.
- Keep calibration appointments. Missing a calibration visit can result in MDDP suspension.
- Document any issues. If you believe a test result was inaccurate, note the circumstances immediately and contact your attorney.
- Don't attempt to tamper. The device has tamper-detection features. Any attempt to bypass, disconnect, or manipulate the device is a criminal offense.
What Happens If You Violate?
Violations—failed tests, skipped retests, missed calibrations, or tampering—are reported to the Secretary of State. Consequences can include MDDP cancellation, extension of the interlock requirement, and potential criminal charges. If you receive a violation notice, contact Andy immediately—there may be legitimate explanations that can prevent consequences.
Related Topics: License Suspension & 90-Day Deadline • First DUI • Second DUI • First 24 Hours After Arrest • DUI Penalties • DUI Evaluation Guide • Service Areas
Frequently Asked Questions
What is an MDDP in Illinois?
An MDDP (Monitoring Device Driving Permit) allows Illinois drivers whose licenses are suspended due to DUI to continue driving with an ignition interlock device installed in their vehicle. The device requires a breath sample before the vehicle starts and at random intervals while driving. MDDP permits unlimited driving—to work, school, errands, anywhere.
How much does an ignition interlock device cost in Illinois?
Ignition interlock devices typically cost $70-$150 per month for leasing and monitoring, plus a $30-$100 installation fee. Total cost over a 6-month suspension period is typically $500-$1,000. Some providers offer payment plans. The MDDP permit itself costs $30 from the Secretary of State.
Who is eligible for an MDDP in Illinois?
Most first-time DUI offenders facing a statutory summary suspension are eligible for an MDDP. You must install an ignition interlock device in every vehicle you drive and maintain it throughout the suspension period. Some exclusions apply, including certain commercial driving situations.
What happens if I fail a breath test on the ignition interlock?
If you fail a breath test (blow above the preset limit, typically .025 BAC), the vehicle won't start. This is recorded and reported. Multiple violations can result in MDDP extension or cancellation. If the vehicle is running and you fail a rolling retest, the horn honks and lights flash until you pull over and shut off the vehicle. It will not shut off the engine while driving.
Can I get an MDDP immediately after arrest?
You can apply for an MDDP as soon as your statutory summary suspension takes effect (46 days after notice). The process involves installing the ignition interlock device, applying to the Secretary of State, and paying the permit fee. Your attorney can help you prepare so the device is installed and the application is ready when the suspension begins.
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