On Aug. 19, the U.S. National Highway Traffic Safety Administration begins its annual “Drive Sober or Get Pulled Over” campaign, running for three weeks through the Labor Day weekend—a time of year when drunken-driving fatalities typically surge. Over the past generation, we’ve made important progress against “driving under the influence,” but the numbers haven’t dropped much recently, and the problem still costs some 10,000 Americans their lives each year.

Members of Alcoholics Anonymous like to joke that when alcoholics...