Your intentions are good, but you would be overstepping your bounds and assuming an inappropriate role by setting it up this way. You could , at least, stop serving liquor at some time before the event is over...you could stress on your invitation that guests should not drink and drive, or , you could not serve liquor at all ? If anyone drinks and drives, if anyone gets into an accident because of this,it won't be your fault or your responsibility...it will be theirs alone. Or, you could provide alternate transport at your own expense, for those who might like to use it. But that gets complicated and also expensive. Most wedding receptions serve some form of alcohol, e.g., wine, champagne, etc., and most guests do not get in their cars and crash. You will have far enough else to worry about and plan for, I wouldn't worry about this aspect. Congrats on your forthcoming wedding!