How Drunk Is Too Drunk to Drive?

Our podcast “The Suicide Paradox” featured sociologist David Phillips, who spoke about his research on copycat suicides (a phenomenon he calls “the Werther Effect”). More recently, Philips has been studying drunk driving. Particularly, he’s been looking at drivers who are merely “buzzed” — with 0.01 percent blood alcohol concentrations (BACs) — and has found that the severity of life-threatening motor vehicle accidents increases significantly at BACs far lower than the current U.S. limit of 0.08 percent. In an email, Philips describes his latest research on buzzed drivers:

My current research, just published in Injury Prevention, shows that even minimally buzzed drivers (with BAC=0.01%) are 46% more likely to be blamed for an accident than are the sober drivers they collide with. This indicates that there is no safe level of alcohol for drivers: any amount of alcohol markedly increases the risk to drivers and their passengers. We reached this conclusion after examining an official, U.S. dataset of more than 570,000 car crashes. The findings have implications for drivers, passengers, police, judges, lawyers, insurance companies, advocacy organizations (like MADD) and regulatory agencies.

The paper, “Official blame for drivers with very low blood alcohol content: there is no safe combination of drinking and driving” (abstract; PDF), is co-authored with Ana Luiza Sousa and Rebecca Moshfegh. The researchers used an official nationwide U.S. database (Fatality Analysis Reporting System) for the years 1994–2011. They found that there’s “no sudden transition from blameless to blamed drivers at BAC=0.08% (the U.S. legal limit). Instead, sole official blame increases smoothly and strongly with BAC (r=0.98 (0.96–0.99) for male drivers, p<0.000001; r=0.99 (0.97–0.99) for female drivers, p<0.000001). This near-linear SOB-to-BAC relationship begins at BAC=0.01% and ends around BAC=0.24%.”