As a rule, it's a bad idea to let pedophiles baby-sit, to hire embezzlers as tax collectors or to give a pyromaniac a key to the fireworks factory. We generally try to avoid inviting dangerous people into situations that encourage them to repeat their destructive behavior. So why do we allow drunk drivers unfettered access to their cars?
That's a good question, for which New Mexico authorities had no good answer. For years, the state ranked among the very worst in the nation in alcohol-related fatalities. So three years ago, it decided a change was in order.
In the past, authorities had relied on license revocations to get drunks off the road. But here's a surprise: People who ignore laws against driving drunk also tend to ignore laws requiring them to have a valid license. For some, taking away their license had all the impact of confiscating their library card.
So the legislature, prodded by Gov. Bill Richardson, imposed a tighter constraint on those convicted of DWI: requiring a device that keeps a car from being operated by someone who's been drinking. Other states have mandated ignition interlock devices for those with multiple convictions, but New Mexico was the first to order them for all first offenders upon conviction.
The results were swift and sharp. Since the law took effect, the rate of drunk driving fatalities has dropped by nearly 20 percent. Nationally, by contrast, the rate actually rose slightly during that time.
New Mexico DWI Czar Rachel O'Connor -- that's her actual job title -- notes that the state's campaign against drunk driving includes other steps as well, from a massive public-service ad campaign to intensive use of sobriety checkpoints. But the interlock rule has been a major factor in the improvement.
At the moment, some 7,000 New Mexicans have to pass a breath-alcohol test before they can start their cars. Adding up all the times that motorists have failed the breath test, O'Connor says, the mandate has prevented 63,000 trips by offenders who have been hitting the bottle.
Now the state has additional evidence that its approach is working as intended.
A new analysis of New Mexico's experience, published in the journal Traffic Injury Prevention, finds that first offenders were 60 percent less likely to be rearrested if they had interlock devices than if they didn't. When the gadgets were removed, their recidivism rate rose to nearly the same level as those who had never had them.