Guides

Each guide pulls the rules from every state we've checked and the fees from every company that publishes them, with a source on each line.

• Best ignition interlock companies in 2026Eight companies ranked on state approvals, fee transparency and published device detail, with the scoring shown.
• Cheapest ignition interlock: 12-month costs comparedWhat a year costs at each company from filed fee schedules, and the programs that cut the bill.
• What is an ignition interlock device?How the device works, what installation involves, who needs one and what it costs.
• What an interlock costs for your whole orderLease, install, calibration and removal added up, plus the fees that aren't advertised.
• Failing a test when you haven’t been drinkingMouthwash, kombucha, hand sanitizer: what can register, how long to wait, and how to contest a violation.
• Interlock violations and what happens nextWhat the device logs, who sees it, and how states treat a missed retest compared with a failed one.
• Interlocks on Teslas, hybrids and other EVsWhat each company says about electric and hybrid cars, and what to ask before the install.
• Can you put an interlock on a motorcycle?Which companies install on motorcycles and what to ask your state.
• Does an interlock have a camera?When it takes a photo, which states require one, and who sees the pictures.
• Help paying for an interlockState programs that cut or waive interlock costs, who qualifies, and what to ask the court.
• Getting the interlock removedWho signs off in each state, the paperwork, and the removal fee.