The New York Times (Well blog), May 14, 2013

“It’s better not to drink and drive, but if you do, keep it under 0.05.” So rhymed William N. Plymat, an Iowa insurance company president and former Prohibitionist who became one of the earliest anti-drunken driving activists in the 1950s.

Mr. Plymat’s plea remains timely, with a revived plan by the National Transportation Safety Board, an independent federal agency charged with investigating transportation-related crashes, to lower the legal blood alcohol concentration to 0.05 percent. The safety board’s report, “Reaching Zero: Actions to Eliminate Alcohol-Impaired Driving,” was released on Tuesday.

The United States has long lagged behind most other countries, which have blood alcohol limits of 0.05 percent or lower. The time has finally come to put Mr. Plymat’s plan into action.

Drunken driving raised few hackles in the mid-20th century. Two decades out of Prohibition, Americans — and alcohol manufacturers — were more likely to extol the virtues of drinking as opposed to warning of its dangers. This mind-set extended to drunken driving, which resulted in relatively few successful prosecutions, even in instances where people were injured or killed. Law enforcement officials told grieving relatives that their loved ones had been “in the wrong place at the wrong time.”

But with the growth of the interstate highway system and proliferation of cars, it became harder to turn away, especially once the Department of Transportation reported in 1968 that up to 25,000 Americans died annually because of drunken driving. By the 1980s, thanks to organizations like Remove Intoxicated Drivers and Mothers Against Drunk Driving, angry citizens, many of whom had lost loved ones in alcohol-related crashes, pushed the issue front and center. States passed over 700 new anti-drunken driving laws between 1981 and 1986 alone, tightening loopholes and strengthening penalties. By 2004, all 50 states had lowered their legal blood alcohol level, which had been as high as 0.15 percent, to the current level of 0.08 percent.

Meanwhile, drunken driving control had become a success story. Annual deaths, now termed “alcohol-impaired-driver-related crashes,” had declined from 25,000 to under 10,000 by 2011.

But can we do better? The safety board’s report says yes, arguing that “success in addressing this safety issue has plateaued.” It points to the fact that one-third of highway deaths are still alcohol-related, and that known effective strategies for lowering injuries and deaths because of drunken driving are underutilized.

In this spirit, the safety board is calling for universal use of ignition interlocks, in which drivers must blow into a breathalyzer with a zero alcohol level in order to start their cars, for all convicted drunk drivers. It also wants broader use of roadblocks, in which police stop random cars and test certain drivers for alcohol, another proven means of deterring drunken driving.

Yet the recommendation most likely to raise hackles is the call for a 0.05 percent blood alcohol level, roughly equal to two bottles of beer, two glasses of wine or two shots of liquor on an empty stomach over an hour — with the caveat that everyone metabolizes alcohol differently.

The notion of having a couple of drinks, often termed “social drinking,” has rarely been the target of government officials, who have reasonably focused on the binge drinkers and chronic alcoholics who drive with especially high blood alcohol levels and are responsible for a vast majority of drunken driving deaths.

But what if we could save another 500 to 750 lives a year by lowering the acceptable blood alcohol level to 0.05 percent? Based on data from other countries that have gone to 0.05 percent, Robert Voas and James C. Fell of the Pacific Institute for Research and Evaluation believe that this is possible, both by discouraging social drinking and driving and creating a “general deterrent effect” among the whole population.

The backlash to the N.T.S.B.’s proposal is predictable. The beverage and hospitality industries, which make money from alcohol, will argue that such a restrictive law will deprive Americans of the pleasurable experience of enjoying a drink or two with one’s meal. Libertarians will decry the new proposal as “neo-Prohibitionist,” another example of the “nanny state” depriving us of our basic liberties.

But here are a few reasons that 0.05 percent makes sense. First, almost everyone is impaired at that blood level, with reductions in performance in areas such as braking, steering, lane changing and judgment. Do you want these people coming at you on the road?

Second, it takes some work to get to 0.05 percent. It is overwhelmingly more likely to happen if someone is trying to get buzzed as opposed to having a couple of drinks over a leisurely dinner.

Third, portable breathalyzers are easily available and relatively cheap. If you are out drinking, check your level before you get in the car and, if you are at 0.05 percent or higher, sit back down, eat something and recheck yourself in an hour. It’s not that much of an imposition if lives are at stake.

Or, better yet, arrange in advance for a designated driver. That’s another underutilized strategy that has been around for decades.