On Patrol

I was just out walking the dog, and when a car turned into the block from behind us I noticed light moving at an unusual angle. When the car passed us I saw it was a police cruiser that was passing its driver's-side spotlight across the house fronts, and presumably also using it to look into the narrow spaces between the houses (in this neighborhood, houses are generally about ten feet apart). I haven't seen cops doing this before. But what about the other side of the street?