Police Speed Measuring Devices

Most speeding tickets and reckless driving by speed tickets in Virginia involve one of three police speed measuring devices: lidar, radar, or pacing. All three techniques have their weaknesses and all require that an officer follow certain procedures to verify the accuracy of their speed measuring device. Understanding those requirements, how those devices work, and what their limitations are is important to any speeding or reckless driving defense.

How Did the Police Measure My Speed?

The Virginia state troopers and some of the local law enforcement officers will write on your ticket which speed measurement device/technique they used. In the notes section of your Virginia Uniform Summons the officer will write: "S-radar" for stationary radar; "M-radar" for moving radar; "Lidar", "L" or "Laser" for LIDAR and "P" or "Pace" for pacing.

Law Enforcement Tracking History

The "tracking history" is an essential part of any speeding ticket no matter the type of speed measuring device an officer uses. The tracking history is a series of observations that the officer makes in order to verify that the speeding ticket was accurate.

A proper tracking history has three elements:

1. the officer must make a visual speed estimation before measuring the speed of the target vehicle;
2. the officer must measure the speed of the target vehicle continuously and as long as it is both safe and reasonable; and
3. the officer should check for potential sources of error in the speed measurement.