LED (Light emitting diode) is now the light of choice for most households, offices, and institutions primarily because of its energy efficiency. Studies have shown that LEDs can be 80% more efficient than other traditional lighting options, such as fluorescent lights and incandescent bulbs. This is because 95% of the energy is converted into light, leaving only 5% turning to heat, which is considered waste. This also reduces the cooling cost of offices and residences.
Fluorescent lights have the inverse situation with 95% heat and only 5% remaining. It seems a logical move for almost all government institutions, making LEDs a standard even for ambulances and police, as LED is used for their light bars.
These police light bars can highlight the versatility of LED lights. There are actually different protocols of light and sirens that the police adhere to.
When the lights on top of a speeding patrol car light up, it indicates that they are responding to an emergency call. Police lights are meant to warn civilians to move out of the way because there could be a police scene taking place. They also use this when they are stopped or parked at actual incidents. It is their way to tell people to avoid or vacate the area.
The LED light bars usually come in two colors. There are red lights that indicate an urgent emergency while the blue lights are only used to inform people that there are police in the area. The blue light serves as a signal for people that the area is covered by police and could also be a warning to possible criminal elements.
There are also white lights for the night-shift officers that will be used for their visibility. These lights will brighten dark areas, also used to illuminate suspects who are traveling on foot or being interrogated or interviewed. There are yellow lights primarily for traffic control, specifically to warn approaching vehicles that there are patrol cars standing by, or slowing down a major thoroughfare. These lights can be used when needed, even all at the same time.
These lights are called tactical lights or tactical colors. Aside from there lights, there are also lights used for patrol cars and unmarked undercover vehicles.
Patrol and Undercover Lights
Police departments use patrol car lights that have base rotators. These lights can turn the lights all the way around (360 degrees), so the light can spread in all directions. These lights can also be on strobe mode and there is a main LED light for normal (daylight) illumination.
For the detectives and undercover police agents, they can use unmarked police vehicles. These are still fitted with interior lights that are hidden from plain sight. Officially, detectives and other plainclothes personnel will have mini light bars that are placed behind the windshield at the back window above the trunk. These lights are hidden (to maintain their covert status) until the time it is needed for an emergency, such as in a pursuit.
Plainclothes officers also have small portable lights hidden until they need to reveal or declare that they are police officers. These lights will warn people and motorists that there is a police emergency or pursuit taking place, so they have to give way.