here is the deal the way I understand it.
D.C has a law giving police officers the flexabilty to arrest anyone that ANY alcohol in their system. That means if you blow a .01 you can be arrested or you could be let go it depends on what the officer sees fit. As far as I know this kind of arrest is different from the DUI or DWI, now D.C. still as the .08 legal limit for DUI/DWI(not sure which)
Well recently people in D.C. and especially the bar owners and resturant owners started raising hell over this law where you can be arrested for .01 BAC saying that it deters buisness. Now don't quote me on this but I think it was just determined in the past two weeks or so that this law was really unfair and they took it off the books. So now D.C. as the same laws as MD as far as levels of BAC .08.