Car Emissions vs. Car Crashes: Which One's Deadlier?

The ever-thought-provoking David Levinson posed a question at his Transportationist blog earlier this week that's worth a longer look: Are you more likely to die from being in a car crash or from breathing in car emissions? If your gut reaction is like mine, then you've already answered in favor of crashes. But when you really crunch the numbers, the question not only becomes tougher to answer, it raises important new questions of its own.

First, let's look at U.S. traffic fatalities at the national level. For consistency with the pollution statistics (more on that in a moment), we'll focus on 2005. That year, there were 43,510 traffic crash fatalities in the United States, according to the National Highway Traffic Safety Administration. That's a fatality rate of roughly 14.7 per 100,000 Americans.