Identification

• RADAR is an acronym that stands for Radio Detection and Ranging. Radar is most often spelled without all of the letters capitalized.
  
  

Types

• There are two main types of radar guns: pulse radar, which uses short, pulses of signals, and continuous-wave radar, which uses continuous signals. Police radar guns are most often Doppler radar, which is a type of continuous-wave radar.
  
  

Function

• Radar guns measure the speed of an object by sending out radio waves. When these waves reflect off of objects, they create a "frequency shift," or a "Doppler shift." The waves then return to the radar gun, and the frequency shift is used to determine how fast that object was moving.
  
  

Significance

• According to RadarGuns.com, of the roughly 20 million speeding tickets issued in America every year, about 13 million of those citations used radar guns.
  
  

Considerations

• Using a radar gun requires a straight line of sight between the gun and the moving object to be measured. Radar guns cannot evaluate the speed of an object that is obstructed by a hill or a curve.