What is Wrong with Mandating Interlocks for Low-BAC, First Offenders?

Most criminal statutes follow one fundamental principle: “Let the punishment fit the crime.” Accordingly, people driving at one sip over the limit shouldn’t be punished with the same severity as the high-BAC, repeat offenders for whom interlocks have traditionally been reserved. In context with other traffic violations, drivers at 0.08 BAC (the nationally recognized per se level for arrest) are less impaired than those talking on a hands-free phone, according to several studies (New England Journal of Medicine and University of Utah).

Interlocks were intended for those criminals who MADD has called a “hardcore of alcoholics who do not respond to public appeal.” While it takes as little as two glasses of wine for a 120 lb woman to reach the 0.08 limit (check out the BAC calculator), most drunk drivers involved in fatal crashes have  BAC levels in excess of .19—the equivalent of seven drinks for an average man. Proposals to mandate ignition interlocks for all offenders would inappropriately make the driver one sip over the limit and the high-BAC repeat drunk drivers equal in the eyes of the law.

The system currently used by most states, which MADD is trying to replace, is called “graduated penalties.” This method properly matches the severity of the punishment with the severity of the crime. You would not punish someone driving 5 mph over the speed limit the same way you would someone going 25 mph over the limit. Why punish someone driving at 0.08 BAC with the same sentence reserved for someone driving at 0.20 BAC?