Well, I think Fargon's mandatory jail time for first offenders is not going to be wildly popular with ANYONE. You're only going to increase the prison population, probably forcing your county to use tax payer dollars to build a bigger jail, and you're going to expose young ppeople to a criminal element that they might not otherwise meet - a bad idea IMO.
Drunk drivers OVER age 25 still kill themselves and other people in huge numbers. Colorado has put some pretty strict DUI laws into effect, and this has reduced the carnage at least somewhat.
I started drinking at age 18, mainly because I hung out with a bunch of older graduate students. It was no problem for me to get alcohol. I suspect that is still true today. Teach responsible drinking as others have said, and strictly enforce the drunk driving laws. That makes the most sense to me.