*shrug*

My data on seat belt compliance, drunk driving incidence are from the NHTSA. Per se laws have been around about forty years and alcohol-related traffic fatalities have been plummeting ever since. How much of that decline is attributable to the increased ease of prosecution provided by per se laws? I couldn't say. Over the same time period, police have devoted increased resources to the problem and public perceptions of drunk drivers have changed - drunk driving bears a higher social stigma now than it once did. Still, it's reasonable to conclude per se limits have decreased drunk driving.