How the BOLO 911 receiver operates.  (ESR) “Emergency Signal Receiver”   The first set of BLUE lights is to warn civilian vehicles of Police emergency activity in the immediate vicinity.   The second row of RED lights is to warn civilian vehicles of fire or ambulance emergency activity in the immediate vicinity.   The third row of  YELLOW lights is to warn civilian vehicles of Trains. “School Speed Zones” and School Bus. “Unloading children” in the immediate vicinity.                         The BOLO 911 sending unit (EST) “Emergency Signal Transmitter” will be located in emergency vehicles i.e. Police, Fire, Ambulances and Trains. The "EST" unit will be activated when the emergency equipment is turned on by police, fire trucks and ambulances in emergency mode, or when School busses opens their door to load / unload passengers during designated school zone or at bus stops and activate the strobe lights at intersections.  The sending unit that is located in the Emergency Vehicles will also send a signal to the traffic control box in the near vicinity.  The signal once it is received will activate a white flashing strobe light that is located on top of all traffic lights in the immediate intersection.  Alerting pedestrians and vehicles that an emergency vehicle will be approaching the intersection.