I agree with MoD about the strict penalties, but the incarceration part is very difficult to implement. Our prisons are already full. which would be more feasible? All of us pay more taxes to build/staff new prisons to house literally tens of thousands of new prisoners that get convicted annually of DUI or do you hit DUI'ers in the wallet hard to make them think twice about doing it again?
Many states have already begun making DUI laws much more expensive in recent years for those that insist on testing them (of course most learn how expensive they've become AFTER they get caught. The shrinking numbers indicate that the tougher laws are moving us in the right direction.
IMHO there is no one thing that will completely eliminate DUI. Death Penalties do not seem to stop people from committing murder. Alcoholic beverages have strong ties to so many peoples lives, plus combine that with our society obsessed with cars, make DUI's seem inevitable. Think about it, a passed out drunk woman is the only chance in hell Nala has in ever getting laid.

But there are many things that could be done to reduce the numbers more including:
1. Taverns, restuarants, winemakers, beverage makers may hate it, but perhaps it's time to make a law to reduce the legal blood alcohol level to .0001 , like it is in Iceland where DUI is rare. Right now how much alcohol consumed makes one legally drunk varies in every situation, which leads many people believe they can drink more than they should. Let's remove the guesswork all together. IF you drink anything and get behind the wheel, you risk catastrophic penalties. I kinda doubt anyone in Congress wanting to get re-elected would vote for that law.
2. make all DUI convictions a felony instead of misdeamor. This way, you end up on probation and if you're stupid enough to get caught again, then your problems really escalate. In addition to the monetary penalties, you lose some other rights, like not being able to vote or hold public office. But don't fret, as a felon, you can still make millions in Philly if you are a scrambling quarterback).
3. standardize federal sentencing guidelines based on some of the toughest states plans. Lengthy Loss of license, big $ fines, insurance surcharges, registration surcharges, mandatory AA counseling, community service, for first timers. Get caught again, perhaps buh-bye car.
Just make it simple, easy to understand, and painful to the wallet to make you think twice about doing it. Unfortunately, there's too much disparity in DUI laws between states.
4. Eliminate legal loopholes. With so many lawyers plea bargaining including those silly "work exception" driver licenses, and judges looking to clear their dockets, many DUI charges seem get reduced to non-moving violations resulting in slap on the wrist. Thus incentive for the violator to resume the same old behavior.
Interesting topic.