Chief’s Corner

Chief’s Corner
By Chief Steven J. Wojnar
Dudley Police Department

The question of traffic enforcement, particularly the use of radar for speed detection, was recently sent to me.  The person was stopped for speeding and some other violations and received a written warning.  The boxes for “radar” and “estimated” were both checked off.  Question was if is correct?

Traffic citations in Massachusetts have three options for speeding violations.  They are Radar, Clocked, and Estimated.  “Clocked” is gauged by following a vehicle for a period and using the speed of the police cruiser as a basis for the violation.  “Radar” is obviously using a speed radar device.  Estimated is self-explanatory.  You estimate the speed of the vehicle.  However, what people may not realize, the estimation process is considered a part of the radar procedure.  When officers are trained in the use of a radar unit to determine speed, the device itself is used to verify the officers speed estimation.  Officers will spend numerous hours observing the speed of traffic prior to receiving a radar operation certificate.  Their speed estimations will be confirmed by using the certified and calibrated radar unit.  Over time, officers can become very good at these estimations.

The reason you estimate the speed of a vehicle first, is due to the fact the radar unit will track the speed of the larger, closer, moving object.  For example, a motorcycle is passing a trailer truck.  You can estimate the motorcycle to be moving faster than the truck.  When the radar unit is activated it will most likely detect the truck first.  This will be true until the motorcycle is close by, at which time it’s speed will be detected.  The estimations assist officers with ensuring the correct vehicle is identified for the speeding violation.

Over time, police officers who routinely conduct traffic can accurately estimate a vehicle’s speed.  They may or may not be able to determine an exact the speed to the letter; however, the estimate is usually within a range of 5-10 mph and they can recognize it to be traveling in excess of the posted speed limits.  Radar units are re-certified on a regular basis and they are to be tested for calibration before and after use.  The purpose of speed or any traffic enforcement is to encourage voluntary compliance with the laws and prevent accidents and injuries.

Thanks again for your questions and comments.  Please send them to me at the Dudley Police Department 71 West Main St., Dudley, Ma. 01571 or email at  Opinions expressed in this weekly column are those of Chief Wojnar only and unless clearly noted, do not reflect the ideas or opinions of any other organization or citizen.

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