Economists believe that, other things equal, people who earn more money have a higher opportunity cost of time. A reasonable inference, therefore, would be that higher income people would want to drive faster. (This is incomplete; higher income people could well have a higher demand for safety, offsetting the higher price of their time. But higher income could also correlate with better health and alertness, making it easier to drive faster. And there are other complications, but work with me here.) Much to the surprise of a Pemco Insurance spokesman, that seems to be the case. (Link via Fark.)