Analysis shows stronger economy can be bad news for highway safety

(December 14, 2015) ARLINGTON, Va. — An analysis of federal crash statistics by the Insurance Institute for Highway Safety shows how economic recessions and subsequent recoveries affect crash deaths. Historical crash data point to the economic recovery as one likely cause of the increase in deaths.

Recent headlines imply that the years of declining traffic fatalities may be over for now. The National Highway Traffic Safety Administration has estimated that crash deaths increased 8 percent during the first six months of 2015. That would put the U.S. on pace for the highest toll since 2008.

As the chart above shows, after peaking in the early 1970s, crash deaths have fluctuated quite a bit while generally trending downward. Large dips in crash deaths correspond roughly with shocks to the economy: the oil embargo of the mid-1970s, the recessions of the early 1980s and early 1990s and the more recent downturn that began with the subprime mortgage crisis.

Much of that is due to people driving less. In the chart, the line showing deaths per billion vehicle miles traveled has a smoother downward trajectory. However, there are dips in that line too, albeit less pronounced. Those probably can be explained by changes in the type of driving people do. Discretionary trips for vacations and evenings out are the things that are likely to be eliminated first, and that type of driving tends to be more risky than daily commuting or trips to the supermarket.

Chart 2 above illustrates the connection even more clearly. It shows the year-to-year percent changes in the unemployment rate, along with the year-to-year percent changes in crash deaths per billion vehicle miles traveled. As the unemployment line goes up, the crash deaths line goes down, and vice versa.

The U.S. economy has been in a recovery for some time, but growth has been slow until recently, which may explain why deaths are rising only this year. A total of 32,675 people were killed on the nation's roads in 2014. That is 44 fewer than in 2013.