Drunk Driving Laws are a state issues. As a DUI defense attorney, I am regularly in the County District Courts for the State of Kansas. My legal practice rarely takes me into the federal courts, where I have only done one jury trial. All my other trials have been in the district courts or the municipal courts. However, more and more the federal government is taking away State rights and giving more power to the federal government. That appears to be true for DUI laws. It appears I may eventually become a "federal" DUI defense lawyer soon.
Funding will be an issue of course. Currently, each counties in Kansas pay the expense of putting DUI offenders in custody. DUI offenders are not sent to prison, where the State of Kansas would be responsible. Rather, DUI offenders go to jail, on the county's dime. Will the federal government really then send people to federal prisons? I doubt it. However, I could see the federal government taking control and then forcing the State/County to pay for it. As Un-Constitutional as that sounds.
Check the folowing article regarding money, DUI, and quotas.