First of all, inequality between rich and poor countries has increased dramatically in the last two decades, with (as James Wolfensohn of the World Bank said) 20% of the world's population controlling 80% of the world's wealth.

BBC: The Lessons of Prague

After controlling for population and the number of police officers in each county, the study found that a one percent point increase in the local unemployment rate leads to a 6.4 percentage point increase in the number of traffic tickets.

FORBES: It's Not Your Imagination. Recessions Do Lead to More Traffic Tickets