You will find that the police car sometimes lights up the police car strobe lights even when it is not moving. This is to warn other drivers and pedestrians of accidents. Sometimes, multiple police cars in an area are found with lights on, which is to tell the public that the police are dealing with the matter and that they should keep off the area or pass their vehicles safely.
Most warning beacons for vehicles are located on the top of the vehicle. They are always visible, even if they are not necessarily open. But sometimes, the police lights are not visible until they are turned on.
This is the case with plainclothes police. They must move around cautiously, but sometimes they also need to move quickly in traffic or attract the attention of pedestrians. This type of police work requires LED dash strobe lights, such as sunshade light bars, which can be placed in the car until they are needed.
When you really need to use the warning lights, just plug them into the cigarette lighter power socket in the car and place them inside the car. They can be up and running in a few seconds, or they can be deleted in a similar amount of time.