Earlier this month, Larry Jones from National Interlock Service met with NTSB Board Member Mark Rosekind and staff to demonstrate how ignition interlocks help prevent alcohol-impaired driving. These devices, which prevent someone from starting a car when his or her blood alcohol concentration is above a specified level, are being used more frequently. 

Ordered for convicted DWI offenders by either the state licensing agency or by Judges, these devices also require retesting throughout a trip (rolling retests) to prevent impaired drivers from having other individuals start the vehicles.  Failing a rolling retest does not stop the vehicle, but activates vehicle lights and/or the horn to warn other drivers and law enforcement of a potential problem.  In addition, “customers” have several minutes to take the rolling retest before the device activates the warning.

CDC researchers determined that DWI re-arrest rates for drivers with these devices decreased by a median of 67 percent relative to drivers with suspended licenses.  Because pass/fail activity is monitored, ignition interlocks also provide accountability, helping DWI offenders to identify and confront potential underlying alcohol problems.  For these reasons, the NTSB includes use of ignition interlock devices as one of the elements in the Board’s model program to address hard core drinking driving.