Twice within the past few years, I have been pulled over by the police for driving at night without my headlights on. My car is supposed to turn on the headlights automatically when the light outside is below a certain level, but sometimes I accidentally brush against the controls and inadvertently switch them to manual.

Both times I thanked the policeman because he may well have saved my life. Neither time did I get a ticket or even a warning. In each case, the policeman was white.