With the errors inherent with radar detection units used in school speed zones, it is clear that radar detection units deployed in Nassau County school speed zones can result in the issuance of tickets in error to motorists driving in full compliance with the law.
Due to these limitations in the technology, this program should be immediately discontinued, all tickets issued should be nullified, and any fees collected should be returned. It is unethical to knowingly ticket any innocent drivers who are driving in full compliance with the law.
Many Nassau County motorists who reported diligently monitoring and controlling their speed have been issued school speed zone tickets regardless.
Their complaints have fallen on deaf ears in the Mangano administration, where the administrators of the system do not acknowledge the inherent limitations of the overly simplistic radar technology in use.
These administrators stonewall those who protest their innocence and instead ignorantly insist upon the infallibility of the radar systems in use.
The https://www.radars.com.au/police-radar-errors.php article is titled “PROBLEMS AND FAULTS WITH POLICE RADAR AND POLICE SPEED GUNS”
Despite the widespread public misconception of the infallibility of police traffic radar (due to the public’s lack of understanding of the technology), radar makes mistakes and is actually very, very error-prone.
Some experts estimate that 10-20% of all radar-backed speeding tickets are issued in error.
Automobile traffic radar is far more simplistic than rotating antenna radar used to track and predict weather, control airport commercial air traffic, and control military air traffic.
Police traffic radar uses a stationary (non-rotating), single antenna that points in a single direction only, does not transmit a modulated signal (versus AM Radio that uses Amplitude Modulation and FM Radio that uses frequency modulation), and does not use a cathode ray or other display screen to display information.
All radar uses a microwave beam on a specific frequency.
Targets that are struck by the beam reflect microwave energy back to the antenna. A computer analyzes any changes in the frequency and makes this information available for further processing or display.
Sophisticated military-commercial type radar uses a modulated beam which provides details about an object’s shape, speed, and direction for the operator. In contrast, police traffic radar with its stationary beam and digital readout of speed yield only one piece of information, which is how fast a target is approaching or receding from the radar antenna.
Police traffic radar, inherently simplistic, does not tell its operator (or its systems interface) which object it is measuring or the direction that the object is travelling.
False speed readings can be due to the presence of CB radios or police radios, among other reasons, which include temperature variations, mis-calibration, and unacceptably wide beam widths.
The beam width concerns the spreading out of the signal as one moves further away from the antenna. It is like a cone that is narrow at the radar antenna but widens as it heads for the horizon. Even the narrowest of radar beams, 11 degrees of angle, is 38-feet wide when 200 feet down the road and 57-feet wide at 300 feet away from the antenna.
Some radar units even transmit a beam as wide as 24 degrees of angle. A radar beam can target an area as wide as an expressway and beyond.
With a roadway having multiple vehicles in motion, and with the radar unable to tell which vehicle it is monitoring, or even whether the target is approaching or moving away from the antenna, one can readily realize the great potential for misidentification.
Another error is due to most radar units not being able to correctly interpret the effect of the Doppler shift.
The phase-lock loop processing logic used to exploit the Doppler Effect can lock onto the wrong target, double or triple low speed readings, and produce “ghost” readings.
Common sources of radar errors include: airport radar; microwave transmissions; transmission of CB, ham, VHF/UHF, cellular two-way radio/telephones including police and business radios; faulty spark plug wires; mercury vapor and neon lights; high tension power lines; and high voltage substations.
The radio energy from these sources can overload or confuse the sensitive circuitry used to interpret returning radar signals.
Mechanical interference includes any moving object, including another vehicle that is a better reflector of radar waves, and multiple targets in the main radar beam, causing multiple reflections and making the display (or the systems interface) read high, low, or blank.
Unless an error condition is recognized, there is a high likelihood of a ticket being wrongfully issued.
The following errors are described in more detail in the article with the assistance of diagrams which make the concepts less abstract.
1. Antenna Positioning Error,
2. Look-Past Error {closest vehicle may not return the strongest signal},
3. Vehicle Interference Error {not applicable to fixed radar antennas],
4. Cosine Error {due to a stationary object such as a building, or a sign, which may be an efficient radar reflector},
5. Double Bounce Error {any bouncing of signals off of other vehicles or stationary objects produces erroneous readings},
6. Beam Reflection Error {any reflection of the radar beam causes erroneous readings},
7. Road-Sign Error {road signs are a common source of erroneous radar readings},
8. Radio Interference Error {any radio transmissions can cause erroneous radar readings},
9. Fan-Interference Error {only affects mobile radar units in motion such as in police vehicles}.
Joseph A. Hobel
