Last Call for Drunk-Driving Posts

Time to wrap up this series on drunk driving, alcohol abuse, and measures we could take to better control them if we so desired. With help from authors Peter Anderson, Dan Chisholm, and Daniela C. Fuhr, I’ve written about measures like programs to persuade people to moderate their liquor consumption (not much evidence of effectiveness), to cut back on the times and places one can buy liquor (more promising), and to increase taxes on alcohol (would definitely work, but perhaps not as effectively as we would hope).
However, as I have noted, all of these measures would affect (perhaps “punish,” depending on your point of view) responsible drinkers, not just the problem cases likely to indulge in crime, domestic abuse or drunk driving.
Thus it may be more fair and perhaps more effective to target troublesome behaviors directly. What potential measures might work for DUI?
Since other forms of persuasion seem to have limited effectiveness, it should not come as a big surprise that designated driver programs have shown equivocal results (see this literature review from Susan M. Ditter and colleagues). Advertising, and programs conducted by drinking establishments (e.g. rewards like free soft drinks for designated drivers), have demonstrated a positive, but quite modest, effect. More study is needed before we can conclude that designated driver programs really work.
Education and persuasion have been shown to be more powerful when backed up by the muscle of the criminal justice system. Over 150 studies have looked at whether court-mandated treatment programs for convicted drunk drivers are effective (see this from E. Wells-Parker and colleagues). The evidence indicates they are. Those who complete such programs get into about 9 percent fewer alcohol-related crashes, and this figure probably understates the effect. Education, therapy/counseling, and probation programs are the most effective.
What else might the justice system do? As I’ve written, reducing the permissible blood alcohol content for driving would probably be quite effective; research has shown that cutting the limit to .05 (it is now .08) would probably save thousands of lives per year. If this is too radical a step, some studies have found that a lower BAC limit just for younger drivers would be have benefits. (I’ll take this up some other time when I consider the troubling issue of safety and young drivers.)
Of course, any BAC limit will only be as effective as its enforcement, and as we all know, this is currently spotty at best. According to Paul Zador, Sheila Krawchuk, and B. Moore, the average person who is caught driving drunk has already gotten away with it 87 times.
What to do about this? Ruth A. Shults and colleagues looked at the effectiveness of one aggressive measure: sobriety checkpoints.
Checkpoints work both by getting drunk drivers off the road and by deterring would-be offenders. There is strong evidence (from 23 studies) that they are effective, particularly when backed up by media campaigns. The median selective breath testing program covered by Shults caused a 20 percent reduction in alcohol-related crashes in its community. If those results could be replicated nationwide, thousands of lives would be saved annually.
Three studies have done a benefit-cost analysis on breath testing, comparing savings from crashes avoided to the costs of the programs; the results vary pretty widely, but all show a high level of net benefit.
The Supreme Court has ruled checkpoints constitutional, but then again tax audits and root canals are constitutional too, and that doesn’t make them any more pleasant. Unquestionably, sobriety checkpoints are an intrusion on our privacy, particularly because they give police the opportunity to check for other violations. Is this worth the lives saved?
A policy that is gaining in popularity and has fewer potential privacy issues is ignition interlock devices (IIDs). These are cell-phone sized gadgets into which drivers must blow in order to start their vehicles. A BAC over the pre-programmed limit renders the vehicles inoperable. You have to blow periodically to prevent you from having a sober “friend” start your car for you. The devices cost $70-150 to install and about $60-80 per month to maintain, at the driver’s expense. (For more see this from Mothers Against Drunk Driving.)
Thirteen states currently mandate IIDs for first-time offenders at the .08 level. Nationwide, one in 10 convicted drunk drivers currently has an IID.
Given that 65 percent of DUI violators who don’t get IIDs continue to drive after their licenses are suspended, IIDs sound like a pretty reasonable idea — provided they work.
The good news is that studies show that offenders who have IIDs really do stop driving drunk; one randomized trial showed their re-arrest rate is only about a third of those who don’t get the devices (see this from Charlene Willis, Sean Lybrand, and Nicholas Bellamy). The bad news is that when the IIDs are removed, drivers quickly revert to their old ways and start driving drunk again as if they never had the device.
Does this mean we might consider mandating IID use permanently, as least for the most serious repeat offenders? Or, taking this to its logical conclusion, might we someday make IIDs mandatory for all?
This might strike many of you as a level of surveillance that could only be devised by the mind of Dear Leader, but after all, zero information besides your BAC is collected, and even that is not distributed to others. Indeed, robot enforcement of this type – red light cameras, about which I’ll write another time, is another – may actually be far less intrusive than justice meted out by humans, and has the potential to be less arbitrary as well. Besides, many of us have voluntarily given Google or Yahoo a vastly better opportunity to pry into our most closely guarded secrets than a humble IID could ever aspire to.
In any event, long before we get to IIDs for everybody we will probably have implemented the solution that will virtually banish DUI with zero privacy intrusion while allowing us to drink and drive as much as we want. Oh, by the way, it will work wonders for our congestion problem and do a great deal to eliminate unfair disparities in mobility for our disadvantaged citizens. This policy gets very little play in our public discourse, but hopefully in the next post I’ll be able to enlist your support.