Ignition interlock device: who installs in your state
An ignition interlock device is a small breath tester wired into the ignition: the car starts only after a clean breath. See who installs one in your state, and book the visit.
You will see which companies install devices in that state and what a first drunk-driving charge (DUI) means for you.
Tap your state on the map, or choose it from the list.
Nine companies side by side
Each company only works in certain states, so not every one is near you. The table shows each company's listed price, how many states it works in and its score on Trustpilot, a review website. All nine compared in full.
| Company | Listed price | States | Trustpilot |
|---|---|---|---|
 Smart Start | from $59.99 a month | 48plus DC | 4.6 of 5 (43,627 reviews) |
 Intoxalock | from $54.99 a month | 48 | 4.4 of 5 (80,912 reviews) |
 LifeSafer | $50 to $120 a month | 47 | 4.6 of 5 (20,439 reviews) |
 Dräger (RoadGuard Interlock) | Call for a quote | 32plus DC | 1.7 of 5 (72 reviews) |
 Low Cost Interlock | from $78.76 a month | 31 | 2.9 of 5 (4,064 reviews) |
 Guardian Interlock | $50 to $120 a month | 31 | 3.7 of 5 (828 reviews) |
 Alcohol Detection Systems (ADS) | Call for a quote | 29 | 2.4 of 5 (13 reviews) |
 ALCOLOCK | $60 to $90 a month | 24 | 2.3 of 5 (46 reviews) |
 Monitech | Call for a quote | 1North Carolina | 4.2 of 5 (791 reviews) |
What an ignition interlock device does
An ignition interlock device is simply a breath tester, roughly the size of a cell phone. It gets wired into your car, and you breathe into it before starting the engine. According to Mothers Against Drunk Driving (MADD), the car won't start if the device finds alcohol on your breath.
The device will ask you to blow again a few times as you drive, at moments you can't predict. These extra tests while you drive are called rolling retests. They check that whoever is driving is the same person who gave the first breath test.
Your costs
- To install
- $70 to $150
- Each month
- $60 to $80
The device is a rental from an interlock company, not something you buy. MADD says installation usually costs from $70 to $150. Then you're paying roughly $60 to $80 each month. The monthly fee pays for the company to check your saved breath-test results and to confirm the device still reads alcohol correctly.
Keeping the device longer means a bigger total cost. Enter the number of months you need in the cost tool to get your total.
When you book, ask about help if money is tight. Drivers who can't afford the device can get help from interlock companies in most states, or from a state fund.