If you have received a speeding ticket from a police officer who was using a laser gun to determine your speed, you may be able to challenge the ticket based on current facts regarding laser gun accuracy. There are several things you should know about how laser guns work and their accuracy which can help you fight a speeding ticket in court.
In the simplest terms, a laser gun sends a pulse of light to your vehicle, where it bounces off and back to the laser gun. The change in distance between the pulses is measured, thus telling the police officer how fast your car was traveling. Even though today's laser guns are considerably more accurate than in the past, both laser guns and their operators are subject to error. In fact, the lowest estimates state that at least 25% of all laser tickets are in error, due to shadowing, RFI interference or mechanical failure or interference. RFI is Radio Frequency Interference and can occur when a poorly-shielded radar gun's speed readings go blank due to a radio or police radar's interference. In 2004 the Pennsylvania State Police bought hundreds of new laser guns, and were stunned to find that the guns were clocking rocks at 70 mph. This is a type of mechanical interference whereby the police car's heater or air conditioning fan interfered with the correct reading.
A laser gun must be held very, very still by the officer in order to get a good reading, and must be held on one part of the vehicle, usually the license plate. If the laser gun "wobbles" or is not held steadily at one point on your vehicle, the reading will not be accurate--the resulting speed can be anywhere from a few miles per hour all the way up to sixty miles per hour off. If you were speeding in less than perfect weather, it is also possible that the laser could have possibly hit a rain drop or snow flake, rather than your vehicle. Beyond these issues, there is the question of whether or not the laser gun has been recently calibrated.
If you have received a ticket through the use of a laser gun, you may be able to challenge the accuracy of the laser and get your ticket dismissed. It would be advantageous to hire an experienced attorney who can help you navigate the court systems, and who will have plenty of up to date information regarding laser guns and operator error. A skilled attorney will be fully aware of the laws in your specific jurisdiction and help you mount a successful defense.