LAST EDITED ON Mar-09-17 AT 07:03PM (MST)[p]There are a lot of factors at play. As jager pointed out, there are studies that show sometimes the least intoxicated can be the most dangerous. Why? Because they are 'fine' and they know it. They drive as always because they are 'ok' in their own mind but simply are not.
Scientifically, the first mental function altered by alcohol is judgment. This is not as noticeable as the other changes such as vision, speech, and other impairment which begin at higher BAC levels, simply because it is judgment which by definition makes it difficult for the person in question to make an objective assessment of.
Experience wise I will say there is a conclusive correlation that any alcohol has a direct increase in driver error. Would you jump on a Boeing 747 if you knew the pilot was a .079 at takeoff? Would you undergo brain surgery while you surgeon was sipping a dry martini? I've seen a lot of dead bodies and made a lot of midnight knocks on doors....usually murphy dictates the non-drinking parties are likely to be victims. Impaired driving is a very selfish and short sighted activity.
It will take some time before the numbers show whether it has a tremendous impact one way or another. Historically, in the US, the limit used to be quite standard at a .10 BAC limit. It took years before states adopted a .08 BAC limit which had a similar reaction to this (many states at the threat of losing federal highway dollars.) Statistically there was a decline in DUI related death and injury. The national highway traffic safety administration has extensive studies that back this up and suggest a lower BAC would continue the trend.
Since Utah is a first in the US to do this one predictor would be to look outside of the US. There are numerous first world industrial nations who have had the lower standard for quite some time. The studies there are quite clear and compelling there is a difference.
I am not trying to argue one way or the other here but rather giving some personal insight. It is interesting for sure. There are also a lot of vested parties one way or another whether that means you are a casual drinker who doesn't want to be trapped after one drink, or whether you have lost a loved one to a DUI driver.
One thing I can say for certain, is for those who drive with any amount of alcohol whether legal or not by definition of this or any other state, do yourself a favor and look into what happens on the civil side should you be involved in a serous injury accident. Even if the exact same accident could have happened alcohol consumption aside, you will be eaten alive in a civil court. Imagine the proposition of being the subject of a wrongful death suit, and your BAC was a .035. If you think the jury will be sympathetic to you on a civil judgment you are more than likely sorely mistaken.
There will be those who are quite cavalier about drinking and driving and I'm sure some will post here. That is certainly their prerogative, but if you look at geographic areas where there is a higher social/cultural tolerance and acceptance to drinking and driving, you will also find more road side memorials. The risk benefit analysis simply doesn't bode well for mixing the two.
Now does that mean I haven't seen some wicked death and injury from other behaviors? Absolutely not. I don't think anyone is suggesting other reckless behaviors be ignored. Again, I have zero interest in getting into an argument one way or the other. Like I say, cost benefit, not worth it, or shouldn't be no matter which side of the fence you sit. The ramifications can be costly and life changing. Uber is pretty affordable by comparison.
Edit. One more thing. Many people do no understand what a legal limit is. The legal limit, or per se in legal Latin, simply means if you are here, the law finds that you are de facto, in violation of the law. It is not nor has it ever been home plate marker.