Expert Fitting Service

LASER has a problem in the USA

Laser Speed Detection - EXPOSED!
From a USA Law Paper

Laser speed detection serves the same purpose as Radar; however, the two systems are totally different beyond their common goal. Laser uses a light beam and takes the measurements based on the speed of light. On the other hand, radar uses a radio beam and measures at the speed of sound, which is substantially less than the speed of light. While radar has a wave length of anywhere from inches to hundreds of feet, laser has a wave length of only 30 millionths of an inch. A typical radar beam is 18 degrees (X-Band) to 15 degrees (K-Band) wide.

Comparatively, laser has a beam that is one sixth of a degree. The results are drastic as the beam radiates out from the laser gun. While radar can expand to over 500-feet wide at a distance of one mile, the laser beam will only expand to 19 feet wide. At a more realistic distance of 1000 feet, the radar expands to over 100' wide while the laser system only expands to 3-feet wide.

Although laser sounds like the insurmountable speed detection system, it is not infallible. In fact, Lidar is significantly affected by weather conditions. Fog and clouds will severely reduce the effective measuring distance of the laser beam. For example, the laser system can only be used from a stationary set up rather than moving like some radar systems. Furthermore, laser can not be used through a windshield in most cases and the operator must have additional training that is typically not required for radar systems. Laser also has a problem getting an accurate reading when used at a severe angle to the target vehicle such as from an overpass or the far shoulder of the road. In addition, maintenance and calibration can only be performed by a factory authorised repair facility. As you can see, laser may be tougher to beat than radar, but it can be accomplished.

The primary target for the laser beam is the vehicle's licence plate. The light beam relies on a reflective surface for the successful return signal. This is why dark low slung vehicles with minimal or no chrome are so hard for laser to detect. The front licence plate should be removed and the rear plate should be painted with a high gloss clear coat to help defeat the laser beam.

Prior to each use, the laser gun should be locally calibrated by using all three of the following methods:

  • The self test button should be used and the reading should be

  • A measurement of a non-moving target should result in a reading of 0 MPH.

  • The sight and audio tone should be tested by panning across a telephone pole. As the sight aligns with the pole, the audio tone should change indicating a positive contact between the beam and the pole itself.

Essentially, the LTI 20.20 Marksman is the main laser gun being used in the UK. The manufacturer claims a beam width of two feet at a distance of 1300 feet. The speed measurement time is one third of a second and the unit is equipped with an audio seek aid for positive target confirmation. The accuracy is alleged to be precise within 1 mph up to 60 mph and within 3% for speeds over 60 mph. Despite this impressive list of performance criteria, the Marksman has some notable downfalls.

For example, tests indicate that the Marksman lacks uniformity and has an unusual distribution of the beam intensity therefore resulting in a deviation from the aiming point. The especially high level of intensity along the right edge creates a deviation in the horizontal direction. What all this technology translates to, is the Marksman can actually detect a vehicle as close as five feet away from the actual target vehicle.

On June 13, 1996, New Jersey Superior Court Judge Reginald Stanton stated that he was not convinced of the accuracy of the LTI 20.20 Marksman. As such, he ruled that any readings taken with the LTI 20.20 would not be accepted as evidence in any pending or future speeding ticket cases.

For a defence strategy you need to be aware of laser's status in the jurisdiction where your citation was issued. Only a few US states have given laser "judicial notice" which is a legal ruling that establishes specific evidence as beyond dispute. Radar has "judicial notice" in every state.

If no judicial notice has been awarded, then the prosecutor will need to have an expert witness testify to the accuracy and reliability of the laser unit. If this expert witness ends up as a manufacturer's representative, you can make a motion to disqualify the witness since he (and his company) clearly has a financial interest in the outcome of the case and therefore, the witness is not impartial.

If judicial notice has been awarded, you certainly want to utilise the New Jersey ruling in your case preparation. The remaining preparation is very similar to a radar case. You need to focus the court's attention on the officer's training, the unit calibration and self-test methods, weather conditions during the time of the citation and the proximity of surrounding traffic. As with any case, your best strategy is hoping for the officer not to appear in court followed by careful preparation in case he does appear.

As yet I have not heard of a case in the UK using the LTI 20-20 faults, but if you know of a similar case let me know.

Did he get you with LASER?

Questions to ask:

  • Are you trained to use this Laser gun?
  • How accurate is the Laser gun, and in what situations? How about when used incorrectly? Due to the Laser beam's narrow path of travel, the Laser gun can be very accurate when it is used correctly. However, if it were used incorrectly, the results can be useless and very misforgiving to you as the driver of the vehicle.
  • How exactly did you obtain my speed?
  • When was the Laser gun last calibrated?
  • Has the gun been subject to any knocks, Laser gun components are delicate and thereby sensitive. The actual gun would have to be stored and handled carefully as to not damage the innards.
  • How was the gun held, Laser guns cannot be mounted in a moving vehicle, because just a minor jolt will cause the reading to be inaccurate. Therefore, Lasers must be mounted and used from a stationary vehicle or on a tripod. Holding by hand is not as good
  • Make a note of the weather and the officers position. (See my section on "Things they don't tell you about Laser Guns")



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