Carl Bialik, the Wall Street Journal’s “Numbers Guy,” says surveys that try to quantify drunken driving in America skewed by lies. Depending on how people were questioned, surveys based upon self-reporting indicate that either 5% or 15% of the nation’s adults own up to driving while intoxicated in the past year. But the data is undermined by the human desire to comply with social norms — to avoid seeming like a reckless boozer, even in conversations with anonymous pollsters. The polls have fueled a controversy over the broader use of dashboard-based gadgets that test a driver’s breath for alcohol.
The devices measure the breath’s alcohol content when the car is started and again every few minutes. If they detect enough alcohol, they kill the engine. Dozens of states require these ignition-locking devices for more-serious alcohol offenders, but Mothers Against Drunk Driving is campaigning for their wider deployment. In the past two weeks, as bills requiring that repeat drunk drivers use the devices have been passed in Hawaii and Missouri, poll numbers have entered the fray. For the first time, an annual federal survey broke down self reports of drinking by state, lending ammunition to proponents of the devices in states with relatively high incidences of drunk driving.