Initially the only type of lighting available was a halogen rotator type of LED Panel new-lights. Advances in technology have now given us LED lights. LED is short for Light Emitting Diode, and the benefit of this light bar LED units today is they use far less power than the older rotating light strobes. The benefit of this is that the modern light bar LED unit can be left on for long periods without flattening the battery of the vehicle. This is an important factor when fitting lighting to emergency vehicles. In the market today, there are two different types of light head used to make light bar LED units. The TIR light heads have internal optics, which help concentrate the beam of light. The TIR light heads also often have a diffuser lens to widen the spread of the light emitted. The second type, which is increasingly used today, is the linear LED light head. This type of light bar LED has a number of LED's mounted in a linear lens. With this generation of linear LED units there is a reflector mounting which gives a far wider and brighter output. Advances in technology mean that the light bar LED units are rapidly evolving into more sophisticated and versatile units. They come in a variety of colors and flash patterns. Crucially they are simple to operate and that is essential in an emergency situation. The light bar LED units perform several functions and can come with tiered lighting that provides alley lighting and take down lights. There is no standard type of light bar LED, as each state has different requirements for its emergency vehicle lighting. The history of emergency vehicle lighting is a fascinating one. From a single simple strobe light atop a vehicle, we emerge into today's vast array of light bar LED units. From its humble beginnings the emergency vehicle lighting has evolved into the bright 360-degree light bar LED units we see on vehicles today. It's hard to imagine a simple light being so effective and hard to ignore should you see one flashing in your rear view mirror!The modern light bar LED units can be left on for long periods of time. The units can be made to be low profile thereby helping to save fuel whilst the vehicle is moving. The construction of the new-lights bar LED diodes means there are no filaments to burn out or indeed bulbs to break. In effect the modern light bar LED units are maintenance free, which in today's tight fiscal times is a huge bonus to any law enforcement or emergency service department. The price of maintaining safety on our streets is justifiable and necessary.