What an ignition interlock device does and when Pennsylvania requires one
An ignition interlock device is a small machine installed in your car's dashboard that measures your breath alcohol before the engine will start. If you have been convicted of driving under the influence (DUI) in Pennsylvania, the court or the Pennsylvania Department of Transportation (PennDOT) may require you to install one as a condition of getting your license back or keeping it valid during a suspension.
Pennsylvania law requires an interlock device for most DUI convictions, even first offenses. The device stays in your car for a set period — typically one year for a first offense, but longer for repeat convictions. During that time, you cannot start your car without blowing into the device, and you must submit to random breath tests while driving.
The interlock requirement is separate from your license suspension. You may be able to drive during your suspension period only if you have the device installed and a valid interlock license from PennDOT. Without it, you cannot legally drive at all.
Key Takeaways
- Pennsylvania requires an ignition interlock device for most DUI convictions, and you cannot drive during your suspension without one installed.
- You must obtain a court order or PennDOT approval for the interlock requirement, then contact an approved service provider to schedule installation.
- The device costs money to install and maintain, and you pay these costs yourself — they are not covered by the court or PennDOT.
- After installation, you must return to PennDOT with proof of the device and a valid inspection to receive an interlock license that allows you to drive.
- You must keep the device in your car for the full court-ordered period and pass all required maintenance checks or your driving privileges will be suspended again.
Understanding your court order or PennDOT suspension notice
Your first step is to know exactly what your court order or PennDOT notice says about the interlock requirement. If you were convicted of DUI in court, the judge will have stated the interlock requirement as part of your sentence. If your license was suspended by PennDOT (for example, after a failed breath test at a traffic stop), the suspension notice will tell you whether an interlock is required to restore driving privileges.
Read this document carefully. It should tell you how long you must keep the device installed and whether you are required to have it before you can drive at all during the suspension period. Some suspensions allow you to drive when ready if you install the device; others require you to wait a certain number of days before the device becomes an option.
If you are unsure what your notice says or cannot find it, contact the court that handled your case or call PennDOT's Driver Services Section at 717-787-2937. Have your driver's license number ready.
Finding and contacting an approved interlock service provider
Pennsylvania does not install interlock devices itself. Instead, you must hire a private company that is approved by PennDOT to do the work. PennDOT maintains a list of approved providers on its website under "Ignition Interlock Device Providers." The list includes the company name, phone number, and service areas.
Call the provider and tell them you need an interlock device installed due to a DUI suspension or conviction. They will ask you for your driver's license number, the date of your conviction or suspension, and details about your vehicle (make, model, year, and vehicle identification number). Have this information ready when you call.
The provider will schedule an appointment for installation, usually within a few days to a week. Ask about the cost of installation and monthly monitoring fees when you call — these vary by provider but typically range from $60 to $150 for installation and $50 to $100 per month for monitoring. You are responsible for paying these costs.
What happens during installation and the first inspection
At your installation appointment, a technician will install the device in your vehicle. The process usually takes 30 minutes to an hour. The device connects to your vehicle's ignition system and may also have a separate handheld unit. The technician will show you how to use it: you blow into the device before starting the car, and if your breath alcohol level is below the legal limit (usually 0.02%), the car will start normally.
After installation, the provider will give you a certificate or letter stating that the device has been installed. This document is important — you will need it to get your interlock license from PennDOT.
Within 10 days of installation, you must bring your vehicle to an approved inspection station (often the same provider) for an initial inspection. The inspector will verify that the device is working correctly and that it is properly connected to your vehicle. Once the inspection passes, the provider will give you an inspection certificate.
Getting your interlock license from PennDOT
After you have the installation certificate and the inspection certificate, you must visit a PennDOT Driver License Center in person to receive your interlock license. This is a special license that allows you to drive only vehicles equipped with an approved interlock device. You cannot drive any other car.
Bring the following documents: your current driver's license (or ID card), your installation certificate from the provider, your inspection certificate, and proof of financial responsibility (car insurance). Some centers may also ask for the court order or suspension notice.
At the center, tell the staff that you are there to get an interlock license. They will verify your documents, take a new photo, and issue the license on the spot. There is no additional fee for the interlock license itself, but you may pay a standard license renewal fee if your license has expired.
Monthly monitoring and maintaining the device
Once your interlock device is installed, you must keep it in your vehicle for the entire court-ordered period. During this time, you are responsible for monthly monitoring appointments. The provider will contact you to schedule these, usually every 30 days. At each appointment, the technician downloads data from the device to check that you have not tampered with it and that you have not attempted to drive with a breath alcohol level above the legal limit.
If the device detects a violation — such as a breath alcohol reading above the limit, a missed test, or an attempt to bypass the device — the provider will report it to PennDOT. A violation can result in an extension of your interlock requirement or a new suspension of your driving privileges.
You must also pay the monthly monitoring fee at each appointment. If you miss an appointment or fail to pay, your interlock license will be suspended and you will not be able to drive legally.
What happens when the interlock period ends
When you have completed the court-ordered interlock period, you do not automatically get your regular license back. Instead, you must request removal of the device and request a new license from PennDOT.
Contact your interlock provider and tell them your court-ordered period has ended. They will schedule an appointment to remove the device from your vehicle and provide you with a removal certificate. Bring this certificate to a PennDOT Driver License Center along with your interlock license.
At the center, staff will issue you a regular (non-interlock) license, assuming your suspension period has also ended. If your suspension period is longer than your interlock period, you may still not be able to drive until the full suspension is over, even with the device removed.
Frequently Asked Questions
Can I drive someone else's car while my interlock device is being installed?
No. Once your suspension takes effect or your court order is issued, you cannot drive any vehicle without an interlock device installed, even if it belongs to someone else. You must wait until your own vehicle has the device installed and you have received your interlock license from PennDOT.
What if I cannot afford the installation and monitoring costs?
The court or PennDOT cannot waive the interlock requirement, but some providers offer payment plans. Contact multiple providers to compare costs and ask about financing options. Some nonprofit organizations may also offer limited financial help — ask your provider or the court about resources in your area.
What happens if I fail a breath test while driving?
If you blow into the device while driving and your breath alcohol level is above the limit, the device will log a violation and may honk the horn or flash the lights. The violation is reported to PennDOT at your next monitoring appointment. Multiple violations can result in an extension of your interlock requirement or a new suspension.
Can I remove the device myself or go to a non-approved provider?
No. Removing the device yourself or tampering with it is illegal and will result in criminal charges. You must use only a PennDOT-approved provider for installation, monitoring, and removal. Tampering also triggers an automatic report to PennDOT and will extend your interlock requirement.
Do I have to keep the interlock device if I sell my car?
Yes. If you sell your vehicle, the device must be transferred to your new vehicle or you cannot drive. Contact your provider when ready to arrange removal from the old car and installation in the new one. You cannot legally drive without the device during your court-ordered period, regardless of vehicle ownership.