The sour economy could get you a speeding ticket.

Huh?

A new study finds local governments — at least in North Carolina — use traffic citations to make up for revenue shortfalls.

Thomas Garrett, assistant vice president at the Federal Reserve Bank of St. Louis, and Gary Wagner from the University of Arkansas Little Rock, examined 14 years of revenue and traffic citation data from 96 counties in North Carolina.

"A one percentage point decrease in last year's local government revenue results in roughly a 0.32 percentage point increase in the number of traffic tickets in the following year," Garrett and Wagner write.

The number may sound small, but it's a statistically significant correlation, they say.

The finding adds credence to something many drivers have long suspected: Safety isn't the only thing motivating cops. Since many municipalities retain the money generated by traffic fines, perhaps traffic enforcement also acts as a bit of a fundraiser, the researchers speculate.

"There is ample anecdotal evidence that local governments use traffic tickets as a means of generating revenue," Garrett and Wagner write. "Our paper provides the first empirical evidence to support this view."

And when the economy recovers, be advised not to step on the gas. The study found no significant drop in tickets after government revenues increased.

The findings will be detailed next month in the Journal of Law and Economics.