The reasons that lead to driving while impaired vary widely. There are all kinds of motivations, and different people find themselves in such a situation. Certainly, a good number of those people have made an error in judgment, and it's simply one episode. In other cases, it reflects a lack of consideration for public safety, or a lack of respect for the law.
As researchers, we try to find ways to better personalize our approach so this risky behaviour can be prevented. There is no easy answer. It must be considered a progressive strategy, with assessment.
I would add one consideration to the discussion. We've observed that alcoholism and impaired driving are not synonymous. They are different. There are alcoholics plain and simple who don't drive, and there are heavy drinkers who constantly drive while impaired.
We must therefore avoid simplifying things, and saying that it's only a lack of judgment. For some, it's a lack of judgment, but for others, it's a sign of a substantial lack of control in relation to alcohol.
For others still, it's a negligent, almost criminal act, and while alcohol is what precipitates the arrest and conviction, it's not necessarily at the root of the behaviour.