[freeloop3]

I don't think it would help much.

If someone is considering whether to drive to an event or get a ride, a coupon isn't going to sway them. They may want to show off their new car, or have the ability to take someone home with them, etc.

For people who drove to the event and drank too much there, they'll worry about their car. Also they'll take offense at being offered a ride. Alcoholics often have a lot of arrogance and would rather risk it than use a coupon to take a ride because they're "out of control", and take that hit to their pride.

This would only work if the law would allow for free transportation to the event, as controversial as that may be.

[sundaeofshock]

Depends on where you live. In a place like San Francisco, people will drive to events because mass transistor starts to suck after midnight. A person who knows they will get a free or discounted ride home may take Bart (as an example) to the event.