How do Fairfax County or Virginia State Police Clock my Speed for Speeding or Reckless Driving Charges?

There are 3 primary methods used to prove speed in the Fairfax County Courts.

Those 3 methods to prove speed are Radar, Lidar, and Pace, and there is some information below about each of them. 

A fourth method, called "visual estimate" is not as reliable, but it is used as a component of enforcement with each of the 3 named above. 

• Radar: This is doplar radar and it requires that the officer have his radar equipment tested before and after the ticket is written.  Generally, they do this using tuning forks that have been tested themselves for accuracy.  
• Pacing a motor vehicle:   This method is simply measuring the speed of another vehicle by looking at your speedometer.  There is no minimum following distance, but the officer will usually testify that they were going the same speed for some amount of time or distance.  
• Lidar:  This is the newest, most "modern" method, but the technology is probably not as fool-proof as they want to make it sound.  Sometimes the officer's won't have good documentatoin to show that the equipment was tested for accuracy, so this needs to be checked in every case.