Related: Ignition Interlocks Sharply Reduce Drunk Driving Fatalities, IIIHS Finds
Ignition Interlocks Stopped the Most Drunk Drivers in Wis. Last Year
A state-by-state breakdown of drunk driving attempts prevented by ignition interlocks shows that a total of 354,372 incidents of driving while intoxicated were averted nationwide in 2017, according to Mothers Against Drink Driving (MADD).

Photo of Guardian Interlock AMS2000 via Rsheram/Wikimedia.
A state-by-state breakdown of drunk driving attempts prevented by ignition interlocks shows that a total of 354,372 incidents of driving while intoxicated were averted nationwide in 2017, according to Mothers Against Drink Driving (MADD).
Wisconsin reaped the greatest benefit with 46,750 avoided drunk driving attempts, followed by Texas with 29,488, and California with 25,105. Drunk driving was defined as drivers with blood alcohol concentrations (BAC) of 0.08 percent or higher.
MADD released the data on April 11 to coincide with Iowa becoming the 32nd state to enact an ignition interlock law.
Ignition interlocks prevent a vehicle from starting if alcohol is detected on the driver's breath. Any attempt to drive while intoxicated is recorded by the device — and the results, according to MADD, prove that ignition interlocks are an effective deterrent to driving under the influence.
"We know that in 2017 alone, the potential for a drunk driver to kill or injure someone was stopped more than 300,000 times, which confirms that drunk driving is a national public health crisis," said Colleen Sheehey-Church, MADD's national president.
All-offender interlock laws reduce drunk driving recidivism by 67%, according to the Centers for Disease Control and Prevention (CDC). Moreover, a recent study by the Insurance Institute of Highway Safety found that states with laws that mandate ignition interlocks for all drunk driving offenders have reduced drunk driving fatalities by 16%.
Presently, 45 states mandate interlocks for at least certain impaired-driving offenders, and 32 states and the District of Columbia have laws that require interlocks after the first offense at 0.08 BAC or higher.
More Safety

The Safest Fleets Aren’t the Ones with the Most Technology
You’ve made the telematics investment. Here’s how to capture the other half of its value and build the safest fleet on the road.
Read More →
Hidden in Plain Sight: Fleet Compliance Risks
Fleet compliance isn't just about having policies — it's about consistently enforcing them. This practical guide reveals six hidden compliance risks common in public sector and shared fleet operations and outlines proven strategies to improve visibility, accountability, and audit readiness
Read More →
NETS Sets 2026 Fleet Safety Benchmark Conference for Indianapolis
The Sept. 15–17 program will feature fleet benchmarking data, case studies, emerging technologies, and implementation strategies while running alongside the NSC Safety Congress & Expo.
Read More →
Off-the-Job Crashes Account for 43% of Employers’ $61.7 Billion Crash Burden
NETS quantifies costs dispersed across fleet, risk, HR, and other departments while providing new per-crash benchmarks for employers.
Read More →
Ram Recalls More Than 1.27 Million 1500 Pickups for Seat Belt Anchor Issue
The recall affects certain 2019-2026 Ram 1500 pickups that may have improperly attached second-row seat belt buckle anchors.
Read More →How Better Visibility Cut Speeding Violations by 48%
Fleet leaders don't need more data, they need clearer visibility into what the data is saying. This case study explores how one utility replaced speeding-event counts with a single metric — miles driven in violation — to strengthen safety and significantly reduce speeding violations.
Read More →
Operation Safe Driver Week: Why the Industry's Oldest Safety Campaign Still Matters to Fleets
A look at how a 2007 enforcement initiative became one of the most consequential weeks on the fleet safety calendar, and what it means for your drivers in 2026.
Read More →
Nexar-Nauto Merger Aims to Give Fleets Better Safety Intelligence Through Larger Driving Dataset
Stefan Heck tells Automotive Fleet that combining more than 10 billion miles of driving history with Nexar's AI models will give fleets deeper insights into driver risk and roadway conditions than either company could provide independently.
Read More →From Silos to Solutions: Relationship Management for Safer Fleets
From telematics adoption and driver accountability to policy consistency and risk mitigation, this episode breaks down what it really takes to build a safer fleet culture without slowing business down.
Read More →
IIHS Launches First Commercial Vehicle Safety Evaluations
The Insurance Institute for Highway Safety has begun evaluating heavy-duty pickups and cargo vans for driver protection. Which models earned top marks?
Read More →
