In the United States, each state sets its own ignition interlock rules and certifies which companies may install devices. Unlike Canada, most states certify several competing providers, so you can usually compare price, service centre locations and features before you choose.
How many interlock companies are there?
It depends on the state. For example, the Texas Department of Public Safety lists 21 approved ignition interlock manufacturers (December 2025 list), while the Washington State Patrol certifies five. Always check your state’s current certified list before you book.
How to choose an ignition interlock provider
- Is it certified in your state? Only a state-certified device counts toward your requirement.
- Service centre distance: you will return for calibration and data downloads on a regular schedule, often every 30 to 60 days, so a nearby centre or a mobile service saves time.
- Total cost: ask for installation, monthly lease, calibration and removal fees in writing, and whether you qualify for a state reduced-cost program.
- Support: look for 24/7 phone support and clear instructions for lockouts and missed retests.
Who needs an ignition interlock in the US?
Requirements vary widely. Many states require an interlock after any DUI or DWI conviction, while others require one only for repeat offences, high blood alcohol levels or to get a restricted licence during a suspension. Your court order or motor vehicle agency letter will tell you what applies to you.
Interlock providers in the United States
Frequently asked questions
How do I find a certified ignition interlock provider in my state?
Your state motor vehicle agency, public safety department or state patrol publishes the list of certified interlock manufacturers. The providers listed here are tagged with the states where we have confirmed their certification.
How much does an ignition interlock cost in the US?
Costs vary by state and provider. Expect an installation fee, a monthly lease and monitoring fee, and a removal fee. Ask each provider for a written quote.
Can I switch interlock companies?
Often yes, but rules vary by state and you may have to pay removal and new installation fees. Check with your state agency first.
