.049? Wow! That's low!
Most states have adopted .08 as the legal limit, though some may still be at the older .10. The Feds have a way of getting what they want (like lower BAC limits) by withholding funds from states who do not comply, but each state is free to set their own rules and punishments.
Many states (like mine) can still charge you with drunk driving even if you blow well under the limit. It boils down to a judgement call on the officer.
Don't get pulled over on my island with any alcohol on your breath or you'll get charged... that's how the deputies here maintain the state record for most DUI's issued - and we're MUCH less densely populated than the metro areas. Since I work swings and come home late, I've been pulled over several times on Friday & Saturday nights for the most chickenshiznit reasons, just so they could see if I'd been drinking. Once they'd ask me a few dozen questions, shine their nightstick of a flashlight back and forth across my face until I'm seeing spots and finally figure out I'm telling the truth about being sober, let me go - never even asking for license, insurance or registration.
Here, they just hit you real hard with the first DUI (stiff fines, license suspension). Add jail the second time (as well as increasing fines & suspension time.) The third time, after your jail and suspension is over, you have to have a breathalizer installed in your car that you have to blow into to start, and blow every several minutes to keep going as well as attend rehab. May the Lord have mercy on you if there's a fatality and you're drunk, regardless of how many previous DUI's - unless you're a high ranking gov't official.