I think they are trying to slowly lower it as not to cause a huge backlash. Kind of like the frog in a pan of water analogy. As for the level in which you're impaired; I think that would do a great deal with metabolism. Some people get impaired quicker and at lower levels than others. I think they are trying to find the golden mean. Where the most people are affected at the lowest possible level.
I have learned over the years that ones opinion towards hot botton issues directely correlates to whether or not it has directly affected them personaly; kIida like gun violence. The problem with that is in most cases it is too late to prevent a tragic event. I do concur that the study does need to further provide average BAC for alchohol related accidents/deaths. .08 is for some two drinks while .05 would be one for and average drinker as oppossed to a portly fellow like myself...You are better off creating BAC key FOBS that will not start the car if the BAC is above a certain limit. I know there are some variations of that out there already, just not sure what. At the end of the day what is more dangerous? an impaired driver? a drunk driver? or is there a differeence?