Some police cars belong to "plainclothes police cars" and are performing special tasks, such as secret investigation and tracking. If the police directly drive a standard police car, they will not reveal their identity. So I only drive some ordinary-looking cars. But there are also special circumstances, such as the suspect being followed. You can't just chase plainclothes police cars. What should I do if I hit a passerby? Then turn on the police lights temporarily.
Sometimes there is a big task, and the standard police car is not enough. Other vehicles in the police station have to install warning lights to perform the task.