OLR Research Report

March 10, 2010




By: Paul Frisman, Principal Analyst

You asked for a chart showing the states that have ignition interlock laws; the parties to whom the laws apply; how states fund the installation, maintenance, and removal of the ignition interlock devices; and each state's costs per offender.


An ignition interlock is a breath-testing device connected to a motor vehicle's ignition system. It prevents the driver from operating the vehicle when it detects a pre-determined level of alcohol in the driver's breath. States require people convicted of driving under the influence (DUI) to equip their vehicles with the devices for specified periods of time.

According to the National Conference of State Legislatures (NCSL) 47 states (all but Alabama, South Dakota, and Vermont) have an ignition interlock law. We have attached an NCSL chart that provides information on the laws and the offenders to whom they apply. The chart is also available on-line at State Ignition Interlock Laws.

As the chart shows, state laws vary based on several factors, including whether someone is a first-time or repeat offender and the offender's blood alcohol content (BAC) level.

According to information published by the Governors' Highway Safety Association in March 2010, 12 states have made ignition interlocks mandatory or highly encourage their use for all convicted drunk drivers, even first-time offenders. These states are Alaska, Arizona, Arkansas, Colorado, Hawaii, Illinois, Louisiana, Nebraska, New Mexico, New York, Utah, and Washington. NCSL, in a January 2010 survey, found that six states – Massachusetts, Missouri, Montana, Oklahoma, South Carolina, and Texas – mandate ignition interlocks for repeat drunk driving offenders and eight states – Delaware, Florida, Kansas, New Hampshire, North Carolina, Virginia, West Virginia, and Wyoming – require the devices if the offender's BAC is higher than 0.15.

In almost all cases, the DUI offender must pay for installing and maintaining the devices. According to the National Highway Traffic Safety Administration (NHTSA) about 20 states offset the cost for indigent defendants, either from fees paid by non-indigent offenders or through arrangements with interlock providers.

According to NCSL, no state has calculated its program costs per offender.

Congress is considering provisions that would require states to enhance and enforce ignition interlock laws.


Program Costs

Ignition interlock programs involve installation and removal fees and monthly maintenance payments. Because the devices are provided by private vendors, cost estimates vary.

According to NHTSA, installation costs range between $100 and $250, with monthly costs ranging from $65 to $90 (http://www.google.com/search?q=nhtsa+ignition+interlocks+what+you+need+to+know&rls=com.microsoft:*&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1). Minnesota estimates installation fees of between $90 and $100, monthly maintenance fees of between $60 and $125, and removal fees of $50 (http://www.minnesotaignitioninterlock.org/cost.shtml.) Pennsylvania says the cost of leasing a device is about $1,000 per system http://www.dmv.state.pa.us/pdotforms/fact_sheets/fs-pub7214.pdf).

Funding Methods

NHTSA says that states generally fund interlock ignition programs through fees and surcharges paid by DUI offenders. State administrative costs vary depending on the particular ignition interlock program they use. For example, states that monitor interlock data on individual offenders will incur higher costs than states that do not. A few states impose additional monitoring fees on offenders to offset these costs.

NHTSA says about 20 states offset program costs for indigent defendants from fees paid by non-indigent offenders or through arrangements with interlock providers. We provide examples from Florida, Michigan, New Mexico, Pennsylvania, and South Carolina.

Funding Interlock Programs for Indigent Offenders

Florida. Florida charges an offender a $12 interlock fee; $70 for installation; $67.50 for monthly monitoring and calibration; and either a $100 refundable deposit or a $5 monthly insurance charge. If the court finds an offender is unable to pay, it may order that a portion of the fine imposed for driving under the influence be used to defray the costs of installation (Fla. Stat. 316.1937).

Michigan. Michigan requires manufacturers of certified ignition interlock devices to provide the device at no cost to people whose gross income is less than 150% of federal poverty guidelines. Offenders whose ignition interlock device is installed under this provision must pay a maximum daily $2.00 maintenance fee (Mich. Veh. Code 257.625k).

New Mexico. New Mexico funds its interlock program through a fee of between $50 and $100 imposed on non-indigent offenders, and an annual appropriation of $300,000 from its alcohol excise tax. Currently this indigent fund covers the cost of installing and removing the ignition interlock device and half the cost of its lease (New Mexico Statutes, 66-8-102.3).

According to a fiscal impact report prepared by New Mexico's Legislative Finance Committee in February, 2010, the indigent fund was in danger of becoming insolvent because of the increase in the number of offenders accessing it. The report notes that about one-third of the 9,000 offenders in FY 09 have been declared indigent for interlock purposes. Legislation has been proposed that would (1) authorize the state's Traffic Safety Bureau, rather than the courts, to determine eligibility for assistance; (2) increase, from 5% to 10%, the percentage of the interlock device fund allowable for administrative costs; and (3) limit payments to indigent offenders to one vehicle per offender and set maximum payments of $50 each for installation and removal of the device, and of $30 monthly to verify its use.

Pennsylvania. Pennsylvania requires ignition interlocks installed, at the offender's expense, on each motor vehicle he or she owns. But an offender who can demonstrate financial hardship need only install the device on one vehicle. To demonstrate evidence of financial hardship the offender must show that he or she (1) has an adjusted gross household income below 200% of the federal poverty guidelines or (2) participates in a governmental assistance program (67 Pa. Code 88.102).

South Carolina. South Carolina requires offenders to pay for ignition interlock devices. It requires individuals who cannot afford the cost to submit an affidavit of indigence to the state Department of Probation, Pardon and Parole. Upon a finding of indigence the department must pay for the device through its Interlock Device Fund (S.C. Stat. 56-5-2941).


Congress, in deciding whether to reauthorize the surface transportation program, is considering provisions that would require states to enhance and enforce ignition interlock laws. Under S. 2920, introduced in December 2009, states would have to enact mandatory ignition interlock laws for everyone convicted of driving while intoxicated, and require the device to be installed for at least six months. States that fail to do this would lose a percentage of highway maintenance funds. More information is available at http://www.ncsl.org/default.aspx?tabid=19159.