Methods of Speed Measurement in Traffic Ticket Cases

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Ever get a speeding ticket and wonder what methods police use to nail people for speeding? Here is some information you might find useful.

In all courts other than the Traffic Violations Bureaus of NYC and Rochester, if you receive a NY speeding ticket you are entitled to ask for a Supporting Deposition so long as you request it within 30 days of the date on your ticket.  The Supporting Deposition, among other things, lists the way the officer verified that you were speeding.  Contrary to popular belief, a radar gun reading is not the only way an officer can prove in court that you were speeding, though being radar-verified makes his case stronger. Here are some common ways New York law enforcement officials determine the speed of cars they are targeting:

Radar uses radio waves to measure speed. There are three common kinds of radar that New York police officers use:

  • Vehicle-mounted stationary radar
    The radar unit is either mounted outside the automobile facing oncoming traffic or within the car-pointing out the rear-view window. Once the police cruiser is parked, a police officer no longer has to monitor the device, he simply waits for the alert to tell him that he has a speeder. There can be numerous issues with the reading, one of them being that it may be close to impossible to make sure that the radar device is only reading a single lane of traffic on a multi-lane road.
  • Handheld radar 
    The police officer has more control using this device; however, the police officer has to keep it still whenever they’re targeting a vehicle. Not only must her aim be precise, but the slightest motion of the arm can translate into a false speed reading.
  • Fixed moving radar
    This radar unit is attached in or on a police vehicle. The unit will take into account the speed of the police vehicle in relation to the car being targeted.

A laser device uses pulses of light in a similar manner to the way radar uses radio waves in order to detect speed. It sends out pulses of light which are targeted at a moving automobile, the light pulse bounces off the moving car and returns to the laser gun where a rapid calculation decides the pace of the moving vehicle.

Police officers drive behind or next to the target vehicle and match the pace of that vehicle, verifying the speed on their own vehicle’s speedometer. If the police are just pursuing the vehicle, they need to make sure they’re maintaining an even distance from your car otherwise the estimate will be inaccurate.

Visual Estimation
Many police officers receive special training in visual estimation of speed when the train at the police academy. They may be shown videos or taken out to a closed road and shown cars driving at various speeds in order to get a “feel” for how fast a particular car is going. Naturally, this is the weakest form of speed verification. Nonetheless, an officer’s word carries a significant degree of credibility in court. Imagine how hard it is to win a speeding ticket trial – even if there is no technical evidence like a radar reading the officer can still take the witness stand and testify that in his professional opinion you were in excess of the speed limit and that is all that is needed for the judge to convict you.

Speed cameras
Some states have cameras that take pictures of your license plate when they detect a car breaking a particular speed threshold. These units can’t verify who was driving, so the ticket is shipped to the registered owner of the car and carries no points.

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