All this will result in is more arrests. The average Joe isn't going to know the difference between .08% and .05%; the only result will be a larger probability in jail time for someone who would otherwise be considered fine to drive today. If we're going to change the numbers in this manner, why not just make it 0% and at least be clear about the message: Drink at all, and you'd better be willing to not drive for a couple of hours.
Wow, do they really put people into jail immediately for drunk driving?
Over here in germany, the worst thing that can happen is you losing your drivers license forever. (That happens if you get caught drunk driving multiple times and over a certain rate).
Normally we have two limits. One hard limit at 0.05% and a soft limit at 0.03%. Once you're over the soft limit, you may drive around, but if you're driving suspiciously or cause an accident that's enough for being punished (usually you have to pay a fine and are banned from driving for a few weeks). Also your insurance might not cover an accident even if you did not cause it when you are above the soft-limit. (Oh and they do not just take the reading of your blood test an hour or two after the accident, but they calculate an estimated blood alcohol for the time of the accident)