So outlining the issue:
I posted the stats the gov't has that says about 5% of drunk drivers that die in crashes are between 0.05 and 0.08. The gov't says around 30 to 35% of impaired drivers die in crashes (2000 to 2006 stats). The last year of gov't assesment I could find (2009), there were about 85,000 cases of impaired driving in the books. About 1/3 of those are caused by teens and 20+.
Cannuck calculates that about 35 or 40 drivers who drive with BAC of between 0.05 and 0.08 die in crashes. The stat leaves out those drivers that are merely injured as well as passengers and pedestrians and their deaths and injuries, property damage, and whatever else may be pertinent. The government thinks crashes caused by drunk drivers alone costs about $10.6 billion per year. (
Smashed: A Sober Look at Drinking and Driving - Transport Canada ). Can't find anything saying how much is attributable to those drivers that are only mildly drunk (below say 0.10 ). I'm also thinking that some drunk drivers were not drunk the same night they'd been drinking but had slept off some of their impairment and still blew over in the morning.
IMO, 0.05 (when driving abilities, like judgement and motor skills, become impaired) is a reasonable limit and I get the impression that the money spent catching and convicting those under 0.01 is a small fraction of the total costs and well worth that small fraction considering the amount of deaths, possibles injuries and the amount of damage done.
Relative likelihood of dying in a crash relative to age and BAC: