Low gas price-induced roadway Armageddon alarmism

According to an article at Grist, the lower gas prices of late are leading to mass death and destruction in the United States of America:

The Federal Highway Administration confirms that people drive more when gas is cheaper. What's worse: an increase in cars on the roads also means more accidents. Guangqing Chi, a sociologist at South Dakota State University, told NPR that 'a $2 drop in gasoline price can translate to about 9,000 road fatalities per year in the U.S.' Yikes.

Conservative readers will, I'm sure, be shocked to learn that the source for this claim was an interview at NPR actually titled "The downside of cheaper gas: More accident fatalities":


Believe it or not, there is a downside to cheap gas, even for consumers. There's a way low prices can end up being very costly. To explain, NPR's Shankar Vedantam talked to our own David Greene.

DAVID GREENE, BYLINE: So when I see gas prices tumbling at gas stations, I usually feel really good about that. You're saying that there's some problems here?

SHANKAR VEDANTAM, BYLINE: Well, I feel really good about it, too, David. But it turns out that cheaper gas does come with a downside. And the downside is more traffic crashes and more traffic fatalities. I came by this analysis of the relationship between gasoline prices and road fatalities in 144 countries. And what it finds is that higher gas prices are associated with fewer fatalities. Lower gas prices are associated with a larger number of traffic deaths.

I spoke with Guangqing Chi. He's a sociologist at South Dakota State University. He's been analyzing the relationship between gas prices and road fatalities in the United States. He told me about one study he conducted that found that a 20-cent decline in gas prices in Minnesota was linked to an additional 15 deaths per year. I asked him what the effect of a $2 drop in gas prices might be across the entire United States. Here he is.

GUANGQING CHI: A $2 drop in gasoline price can translate to about 9,000 road fatalities per year in the U.S.

GREENE: Nine-thousand? Shankar, I mean, I know we haven't seen a $2 drop in gas prices in the country. But he's estimating that a drop like that could cause an additional 9,000 road deaths? That really scary.

VEDANTAM: It is scary, David. My jaw dropped when I heard that number. Now, even if we take a more conservative estimate than Chi let's say a third of his estimate – that's still 3,000 lives a year. It's an enormous number of people.

The whole interview reads like a fantasy in social engineering 101.  Namely, keep gas prices high in order to save lives.

As Ronald Reagan used to say: "Well, the trouble with our liberal friends is not that they're ignorant; it's just that they know so much that isn't so."  This would be another case of that truism.

The U.S. Energy Information Administration keeps track of inflation-adjusted gasoline prices back to 1976.

And here are the motor vehicle fatality rates over the same time frame – the latest data available from the National Highway Traffic Safety Administration are for 2012.

Major problems exist with the "lower gas prices equals roadway carnage" narrative.  Between 1976 and 1980, gas prices skyrocketed.  Motor vehicle fatality rates did, too.  That wasn't supposed to happen.

From 1980 to 1986, gas prices declined dramatically.  So did motor vehicle fatality rates.  That wasn't supposed to happen, either, if we buy into the sociology theory.

From 1986 to 2002, gas prices were approximately constant, but roadway fatality rates continued a rapid decline.  This contradicts the theory, too.

Supporters of the theory may point to the recent sharp decline in fatality rates between 2006 and 2010 as evidence for their cause.  But real gas prices were effectively equivalent in these two years.  Another theory fail.

From 2009 to 2012, gas prices increased dramatically.  The motor vehicle fatality rates were essentially unchanged.

Throughout the four-decade dataset of gas prices and motor vehicle fatalities in the U.S., there appears to be no evidence that "a $2 drop in gasoline price can translate to about 9,000 road fatalities per year in the U.S."  Indeed, real gas prices did drop about $2 per gallon between 1980 and 1986.  What happened?  The absolute number of fatalities declined – not increased – by 5,000, and the fatality rate also declined by 15 percent.

Perhaps there is some counterfactual multiple linear regression equation out there in the academic literature purporting to show that lower gas prices equal large increases in road deaths, but when every period of the historical record contradicts any such relationship, we must reasonably question the theory.

Then there is the theory that lower gas prices lead to an explosion in driving.  Problems here, too.  Between 1976 and 1980, real gas prices increased by more than 40 percent.  Vehicle miles traveled per person also increased, by 5 percent.  That contradicts the theory.  From 1986 to 2002, real gas prices stayed constant while per capita vehicle miles traveled increased 30 percent.

Since 1994, there is actually a positive correlation between real gas prices and per capita vehicle miles traveled.  That is the complete opposite of what the sociological theory predicts.

Even when we normalize the data to vehicle miles traveled per licensed driver, the correlation is still positive – in contradiction of the theory.  From 2009 to 2012, the real price of gas increased more than 44 percent, while vehicle miles per licensed driver were unchanged (a tiny decline of only 0.6 percent – within the measurement error).

Low gas prices are great news for the economy and our personal freedom, and there is no evidence they are going to lead to a roadway apocalypse.  In fact, relaxed drivers are safer drivers, and knowing you can operate your vehicle at much lower costs is very relaxing.