Daniel assumes police cars have always been black and white everywhere.

They have not. And the origin of the ones that are is murkier than most people expect.

Black was common on early American cars because it was an inexpensive factory finish. As police departments grew, the problem became recognition -- a dark patrol car blended in with civilian traffic. Departments began experimenting with contrast. Black and white police cars were appearing in California by around the early 1930s, though nobody seems to know exactly which department started it. There was never a national rule requiring it.

What spread the image was television. Dragnet put LAPD black and white patrol cars in front of millions of Americans from the 1950s. Adam-12 did the same through the late 1960s and 1970s. Television did not invent the black and white polic ...