I was alerted to a WSJ article where the NTSB was recommending the BAC threshold be lowered to 0.05 in an effort to reduce drunk driving and highway fatalities. At first this sounds like a great idea. Lower the limit, people will be less intoxicated, they will have fewer accidents and ultimately less fatalities. The problem with that logic is those in the public who are causing the fatalities are not blowing 0.08, they are blowing/testing much higher. What lowering the limit will do is cause more citations when someone is pulled and asked if they have been drinking and they say yes, two beers with dinner. Now instead of being free and clear, that person may be at the edge of 0.05 depending upon their weight and what they ate for dinner and may have some explaining to do.
Let’s be realistic, the people causing highway fatalities are not the ones who have a glass of wine, mixed drink or a beer with dinner. It is the party animal or alcoholic who overindulges and then believes they are bulletproof. It is the person who crosses the median and goes into the other lane or even worse goes the wrong way on the interstate because they are so drunk they could hardly walk let alone drive. It is Reese Witherspoon’s husband weaving across the line while she lies to the police about being pregnant because she is blitzed out of her gourd.
I can see where we are headed with this, zero tolerance and everyone with a breathalyzer installed in their vehicle. Prohibitionists would love to see this happen. I personally strive to never drive with a BAC higher than the legal limit and most of the people I know do the same. I try to not consume too much and if I feel I have consumed too much I don’t drive or I try to make sure I am staying home. Further reducing the BAC is just not a good idea since it is based in a fantasy world where everyone obeys the law. Changing limits is generally not useful when it comes to driving. If everyone drove up to and never over the speed limit then we probably could stop many, many more accidents. Would changing the speed limit have any effect on those who show blatant disregard for it in the first place?
Bangers and Mash 
Agreed, people who disregard the idiocy of driving drunk to do it anyway are still going to do it no matter the legal limit. This wouldn’t prevent very many, if any, accidents, but by proposing it the NTSB committee that came up with the idea can act like they’re earning their paycheck and doing good for society.
Neo-Prohibitionism at its finest… as you mention, lowering the limit makes no sense and only serves to punish those who are being responsible. The article mentions Europe’s lower limit, and not to make excuses but Europe has much better mass transit and alternate forms of transportation. I wonder if they considered the fact that Europe’s alcohol consumption on average is twice that of the rest of the world…. Just sayin’, picking and choosing data points…