I don't now how accurate this site is:
http://bloodalcoholcalculator.org/#LinkURL but I looked at it to see how much a guy like me could drink and if this proposed change would make any difference.
I'm a 190 lb male.
3 beers in 45 minutes would put me just over 0.05. 5 beers in 90 minutes would put me over 0.08. I never drink that much, especially in that amount of time, but I remember back in my younger (college) days when I and everyone else would pound them back pretty quickly. Regardless, is you are going to drink that much, you should have a DD anyway.
So if 5 beers in 90 minutes puts me over .08, what if the new standard was .05? I'd have to nurse the same amount of booze, or stop drinking and wait, for two more hours to get under the .05 threshold.
I found it interesting that 4 beers in 120 minutes gave me the same BAC as 3 beers in 45 minutes, just over 0.05.
My takeaway from this proposal, if the states adopt it, is that it won't really effect the casual drinker like myself. It's the binge drinkers who have to watch out. If you routinely have 5 or more drinks (at my bodyweight), who better be prepared to wait a hell of a lot longer before driving (which you should anyway), or you'll need to drink less (which you should anyway), or just get a DD in the first place (which you should anyway).
And if I don't sound old-fogey-ish enough, I'll add that with all the trouble caused by people when they are drinking a lot, a little bit more restrictiveness does not bother me at all. Damn kids anyway!
Therefore, I support this proposal! And I say that as a man who really enjoys his beer.