Mothers Against Drunk Driving (MADD) has released a new report showing that ignition interlocks have prevented more than 5.7 million attempts by alcohol-impaired drivers to start their vehicles over the past two decades.
Ignition interlocks are small in-car breath-testing devices connected to a vehicle’s ignition system following a drunk driving arrest or conviction. If the device detects alcohol above a pre-set limit on the driver’s breath, the vehicle will not start. Currently, 34 states and Washington, DC, require ignition interlocks for all drunk driving offenders.
In 2025 alone, ignition interlocks blocked more than 336,000 attempts by drivers with a breath alcohol concentration (BAC) of .08 or higher—the legal limit in every US state except Utah, where the limit is .05. That is an average of 922 every day or one every 95 seconds.
“MADD has long recognized that technology can play a vital role in preventing impaired driving before it happens,” said MADD CEO Stacey D. Stewart. “This report demonstrates that ignition interlocks are one of the most effective tools available to stop repeat offenses and reduce risk on our roads. Each prevented start represents a drunk driving crash that may never happen, an injury that may never occur, or a life that may never be lost.”
