False Positive Ignition Interlock Readings

Today I met individually with three ignition interlock device manufacturers. To their credit, each one admitted that their interlock devices use fuel cell technology and that ignition interlocks can and do generate false positive readings. We discussed the most common source of false positive blood alcohol readings, which is contamination. This occurs when the device mistakes another substance for blood alcohol.

There are many types of alcohol and the interlock devices often cannot differentiate between the ethyl alcohol contained in liquor and other alcohols such as the sugar alcohol found in protein bars, the sorbitol found in sugarless gum, the menthol found in cough drops, or the multiple alcohols which mouthwash contains. Also, hand sanitizer contains 62% ethyl alcohol. Using hand sanitizer shortly prior to blowing into an ignition interlock device can therefore result in a false positive reading.

In Massachusetts, interlock violations can result in 10 year or lifetime license suspensions. Therefore, interlock users should be mindful of the possibility of false positive interlock readings. Under the Massachusetts ignition interlock program, users who have positive alcohol readings will be called into the Mass. RMV in Boston for an interlock violation hearing. The results of this interlock hearing will determine if the driver will lose his or her license for 10 years or life for the alleged violation.

Many ignition interlock users do not believe that the Registry will actually suspend someone’s license because of an interlock reading. They are wrong. The Registry routinely suspends people’s licenses based on ignition interlock results. 

If you have received an ignition interlock violation notice from the Massachusetts Registry of Motor Vehicles, you should immediately contact a qualified and experienced ignition interlock attorney. I know interlock inside and out. If you have been accused of a interlock violation, do not risk a license suspension; contact me for a free consultation and case review.

Attorney Brian E. Simoneau