Ignition interlock device cost and how to plan for it

Interlock programs in the United States are usually paid for by the driver. The provider owns the equipment and leases it to you for the length of your requirement. The bill is built from several parts.

• Installation. A certified technician wires the control module into the vehicle's starting circuit and mounts the handheld unit. This is a one time charge at the start.
• Monthly lease and monitoring. This is the largest part over time. It covers use of the device, data storage and the reports the provider sends to the court or state agency.
• Calibration and service visits. The program requires regular visits so the provider can download the data and check the sensor. Some providers include these in the monthly fee and some charge per visit.
• Removal. When the requirement ends, the device must be removed by the provider, which may carry its own fee.
• State fees. Many states charge program, license reinstatement or restricted license fees that are separate from what the provider charges.
• Optional or extra items. Insurance against damage to the unit, a camera or real time reporting feature where the state requires it, or a charge for moving the device to another vehicle.

Why the monthly fee matters most

Installation and removal happen once, but the lease and monitoring fee repeats every month for the whole requirement. A program that lasts several years costs far more in total than a short one, even with the same provider. When you compare offers, multiply the monthly fee by the number of months in your order and add the one time charges, rather than comparing installation fees alone.

Two drivers can pay very different totals for the same kind of device. The main reasons are listed here.

• Length of the requirement. Set by the court or the state, and it can be extended after violations.
• Your state. Some states regulate what providers may charge, and some add their own program fees.
• Required features. A camera, GPS or cellular reporting can add to the monthly fee where the state requires them.
• Service schedule. More frequent calibration or download visits mean more visits to pay for, if they are not included.
• Violations. A failed test, a missed rolling retest or a missed appointment can bring extra visits, lockout reset charges and a longer program.
• Vehicle type. Push button start, hybrids and some newer vehicles can make installation more involved.
• Distance to a service center. Not a fee, but travel time and fuel for every visit add to your real cost.

The cheapest way through an interlock program is a clean record. Missed appointments and violations are among the most common reasons the total grows, so plan visits early and keep the vehicle battery healthy, since a dead battery can be logged as an event.

Many states run indigency or financial assistance programs for interlock users, often funded by fees paid by other participants or by the providers themselves. Eligibility is usually tied to income, for example receiving public benefits or earning below a set level, and the help may come as a reduced monthly fee or a share of costs covered by the program.

To find out what exists in your state, ask the state DMV or the agency that runs the interlock program, and ask each certified provider directly whether they offer a reduced rate. Your attorney or probation officer may also know which local programs accept new applicants. Apply before installation if you can, because some programs do not apply discounts retroactively.

Before you sign a lease, ask each certified provider the same questions so you can compare offers fairly.

• Is the provider certified by my state for my type of requirement?
• What is the installation charge, and does it differ for my vehicle?
• What does the monthly fee include, and are calibration and data downloads part of it?
• How often must I come in for service, and where is the nearest service center?
• What do you charge for removal at the end of the program?
• Are there fees for a lockout reset, a missed appointment or an after hours call?
• Is there a deposit or damage insurance, and is it required?
• Do you take part in the state's financial assistance program, and how do I apply?
• What happens to the fee if my requirement is shortened or extended?

Ask for the answers in writing, and keep a copy of the fee schedule the provider publishes. If something on your bill does not match it, you have something to point to.

A personal breathalyzer cannot replace an interlock and it does not lower what the program charges. What it can do is help you understand how alcohol from the evening before is clearing, so you avoid a failed morning start that leads to a lockout, an extra visit and a longer program. If you choose one, a fuel cell model is the closest to the sensor inside an interlock, although the two will not always agree to the decimal.

This is an estimate. It cannot tell you whether you are safe or legal to drive. If you have been drinking, do not drive.

To see how the device itself works, read our guide to the ignition interlock device. To understand the numbers involved, read about blood alcohol concentration and how long does alcohol stay in your system. For personal testers, start with the fuel cell breathalyzer category or our guide to a breathalyzer for car owners.

General information and never legal or financial advice

Interlock rules and fees change, and they depend on your state and your case. Check your court order, your state DMV and the provider's published fee schedule for the figures that apply to you, and speak with a licensed attorney about your obligations.