of an emergency vehicle's lightbar. Take-downs are used on police cars to illuminate the interior of a vehicle immediately in front of the police car, such as a vehicle that has been pulled over after committing a traffic violation or while conducting a high-risk vehicle stop (also called a felony stop). The bright lights also serve to blind the vision of suspects looking back toward the police. Take-downs are also used on ambulances and other vehicles to illuminate a work area in front of the vehicle, such as a patient in the roadway, an accident scene, or a fire scene. Communications devices Efficient emergency responses require that emergency responders can communicate with a dispatcher, with each other, and often with other facilities (such as hospitals or public utilities). Emergency vehicles are equipped with the following types of equipment to do so: two-way radio, usually operating on dedicated frequencies and channels designated for emergency use, or in some cases simply a CB radio. portable two-way radios, which transmit and receive on the same frequencies as the built in two-way radios, but are less powerful. Emergency workers can take these radios with them when they exit the vehicle. There are also systems (frequently referred to as mobile extenders or mobile repeaters) that allow the portable radios to be relayed through the vehicle's more powerful two way radio. Some emergency services encrypt their radio transmissions. car phones or portable cellular phones. mobile data terminals, or MDTs, which are computers that communicate with the dispatcher's computer. Laptop computers with Wi-Fi connections, usually with a mounting point or docking station within the vehicle. These can be used as an alternative to MDTs. PA or bullhorn to communicate with other workers, or with members of the public. Most electronic sirens are equipped with a PA. dashcams, usually video and audio equipment used during DUI stops, inclusive of bodycams worn by on duty police officers Service/unit-specific equipment Different services require different types of equipment at emergency scenes (ambulances and fire trucks carry different types of equipment), and within one service, different units may require different equipment. Medical services Ambulance Helicopter Air ambulance Fire Fire service units and their role differ between countries. Fire apparatus Police Armed response vehicles/SWAT vehicles Motorway/highway patrol vehicles Police car Police aircraft Police motorcycle Police van See also Teardrop light Blues and twos References External links paper discussing safety equipment on police cars,