Are Ignition Interlocks Effective in Reducing Deaths from Traffic Crashes?

Ignition interlocks are designed to prevent intoxicated drivers from driving their vehicles. They require that the breath sample be free of alcohol before the vehicle’s engine will start. But are ignition interlocks effective in reducing deaths from traffic crashes?

interlocks effectiveResearchers explored that important question. Some states require interlock ignition devices on the cars of all persons convicted of drunk driving. They compared the alcohol-related traffic crash death rates of states with and without such laws. There were 18 states with these laws and 32 without them. The researchers used data estimated by the National Highway Traffic Safety Administration (NHTSA).

The effects of the laws were apparent three years after their implementation. The alcohol-related traffic crash rates in states with the laws was 4.7 per 100,000 drivers each year. For the states without the laws, the rate was 5.5. That’s a 15% advantage enjoyed by states with the law.

There are many problems with ignition interlock devices. Someone other than the driver can blow into the sensor. The devices don’t actually measure blood alcohol concentration (BAC). They only estimate it. The devices are subject to significant error. These factors can harm individual drivers. Yet the devices appear to be effective in reducing alcohol-related traffic fatalities.

The researchers drew a reasonable conclusion. ‘Interlocks are a life-saving technology that merit wider use.’

Source: Kaufman, E., and Wiebe, D. Impact of state ignition interlock laws on alcohol-involved crash deaths in the United States. Am J Pub Health, 2016. ePub(ePub): ePub. DOI 10.2105/AJPH.2016.303058.

Resources: Ignition Interlocks Effective in Reducing Deaths

Carter, P., et al. Alcohol ignition interlock installation in new vehicles as a Primary Prevention measure to decrease alcohol involved crash fatalities and injuries. Alc Clin Exper Res, 2013, 37, 149A.

NHTSA. Model guideline for state ignition interlock programs. Ann Emerg Med, 2014, 63(4), 474-83.

Nelson, T. Patterns of change in implementation of state alcohol control policies in the United States, 1999’“2011, Addict, 2015, 110(1), 59-68.

Palmer, T. Alcohol Ignition Interlocks: Effectiveness and Case Studies of Six States. NY: Nova, 2015.

Raub, R., et al. Breath alcohol ignition devices: controlling the recidivist. Traff Inj Prev, 2003, 4(3), 199-205

Tiessart, E. Alcohol Ignition Interlock Programs. NY: Nova, 2014.

Ullman, D. Locked and not loaded: First time offenders and state ignition interlock programs. Int Rev Law Econ, 2016, 45, 1-13.