Some ways that could prevent drunk driving are out of your control meaning you can't do anything about it, and other things are in anyone's control meaning it is preventable. Here are some ways:

In your control:

-If you see someone weaving, tailgating, driving really slow, making wide turns, etc. Just driving stupid then they're probably driving drunk and you could call the cops and stop them.

-You could volunteer to be a designated driver at a party.

- if you see someone leaving a party about to drive, and they're not completely sober, but you are, don't let them drive home drunk and offer to take them home.

-if you go to a party, make sure you plan out how you're gonna get home, because you don't want to be driving home drunk.

Ways to prevent drunk driving

Out of your control:

-The consequences that happen when you drive drunk such as; automatic license revocation, mandatory jail sentence, confiscating license plates. You can't make or enforce the laws, so there's really nothing you can do about this.

-What would be helpful is installing a breathalyzer inside every vehicle and you have to have a breath test before you drive, but you can't control everyone's vehicle all though it would help.

-Another way is to have a sobriety check stop every few miles or so. This could save many lives and would be a great way to prevent drunk drivers.