Why isn't a cognitive reactionary type test offered where you can set your own limit...
You run through these tests after having various amounts of alcohol. When you miss a problem or exercise your limit is .02 below that level so if you get pulled over and blow at your listed level or above. No license for a year 30 days jail the works. Automatically

so you have petite little blonde that can barely drive as it is because omg Harry kissed Stacy and posted it to Facebook her test level is .04 or
A 250lb muscular gentleman who went a the way to .1 safely I know who I would rather be on the road with.

Some of the people I see driving at all or while texting talking on the phone etc is 100 times worse than me having two beers at dinner.