Yes, there is such a thing.
Jason Torchinsky of Jalopnik.com views this as a public service and it's hard to argue with his logic. He says most of us, by now, have the headlight pattern of the iconic Crown Vic burned into our brains...
And all across the country, those venerable Crown Vics are being put out to police pasture; and replaced with any number of different model vehicles as successors. "What this means for us, the generally law-abiding yet still all-too-human drivers of America, is that we need to learn a new set of headlight patterns for police cars. There's plenty of news ones out there..."
To help everyone learn, Torchinsky made a chart of headlight patterns. It's very schematic, since there's no way to know what your atmospheric or glare conditions will be, but if you learn these patterns and train yourself to get off the throttle when you see them, he's betting that we'll all remain happier, less-incarcerated drivers.
Cop Headlight Spotters Chart
Crown Victoria; Dodge Charger; Chevy Caprice; Ford Taurus; & Ford Explorer. With those vehicles he's probably covered 95 percent of the police vehicle fleet in the U.S.
This spotter's guide may be helpful but we hope you'll agree that it's always best to simply drive attentively and stay within the speed limit.