by Mohammed HAMUTH

You have been pulled over. Your hands are sweating and your heart is pounding. A lot of things are going on in your mind. All passing motorists give you a look. The policeman says you have been caught speeding by a hand-held radar, and issues a ticket.

What do you plead? Guilty or not guilty?

DON?T JUST PAY UP! Remember, there is nothing unethical about pleading not guilty even if you really did it. Technically speaking, pleading not guilty is merely exercising your right to question the prosecution?s evidence. You are innocent until your guilt is proven beyond a reasonable doubt. That?s the prosecution?s job. Unfortunately, the system nowadays has turned into a money-making system and you have to prove yourself innocent. If enough people fight it, this revenue-generating system will collapse. Yes, it is a revenue generating system, as a recent incident involving a local radio station showed. In that case, the radio informed the public of the locations of the speed traps. The police complained that drivers were being made aware of ?Mr Brake? and they slowed down, leaving policemen sitting idle, with no culprit to catch! Ironically, the police should have rejoiced that the radio was contributing to the campaign by sensitising motorists! But no, they were losing revenue!

At least, if you fight your ticket, the policeman has to go to court and there is one less officer out there writing tickets for the day. If everyone fights their tickets then policemen either will have to get off the streets or miss trials. If they miss trials, it is to your advantage. You are not wasting police time by getting them to court. Police time is already wasted by running silly speed traps in the middle of motorways. Imagine if your house is being burgled, or your car is being stolen, or your child is being attacked, and all police officers are too tied up running speedtraps hidden behind a bush, with a radar gun, unable to assist you. By abolishing the ridiculous hidden speed traps, many policemen can then be freed to do more useful tasks, such as... you guess it... catching real criminals. Please note that people are not against speed restriction. Those who violate the law, drive recklessly and ignore traffic signs and speed rules should be punished. But what we are exasperated at is the indiscriminate way in which innocent motorists are harassed by a handful of unscrupulous policemen, abusing their authoritative power. However, it is also possible for an honest policeman to wrongly catch a driver who is under the limit, simply because the policeman is relying on his radar. It is indeed possible for motorists travelling under the speed limit to be caught ?speeding?, as it happened to myself! Why?

Well, first of all, let?s explain how the radar works. Through some research, I have gathered the following: Think of a radar unit as a flashlight. Instead of emitting visible light, radar emits invisible electromagnetic waves at a certain frequency. When you shine a light beam from a flashlight over an object, the light is reflected back to your eyes so that you can see the object. The same principle applies to radar beams. The electromagnetic wave that radar emits is called microwave, which will reflect off most metallic objects, concrete, trees, wood etc. It will however go through grass, bushes etc., just like light will go though glass and transparent objects.

The radar unit uses an antenna to ?read? the microwave that is reflected back from an object (such as a car), just like you use your eyes to capture the reflected light from your flashlight. If the microwave from the radar hits a moving target, the waves? frequency will change based on the ?doppler shift? principle. With the reflected wave?s changed frequency, and the known frequency that the radar emits, the computer inside the radar unit will be able to calculate the target speed. Note that radar cannot determine the target speed when the target is travelling perpendicular to the radar beam, since there will be no doppler shift relative to the radar antenna.

It?s that simple. However, there are many shortcomings to traffic radar. First of all, radar is prone to interference. It is not too hard to figure out that the radar?s antenna will accept any microwave that it is able to ?hear?. High voltage power lines, telephone lines, power stations, even neon lights, do emit lots of electromagnetic waves. There is absolutely no way to tell which wave the antenna is hearing. Secondly, radar cannot determine which target reflected off the waves. If there are two cars both travelling in a close proximity, no one can tell who is responsible for the radar reading if such is obtained. Identifying the target is a job left to the radar operator, therefore it?s a human mind and eyes that determine the target, and mistakes are bound to occur. At a distance of 200m, the width of the radar beam can usually cover all 4 lanes of traffic travelling in both directions. In other words, it is impossible for the policeman to know exactly which vehicle is responsible for the radar reading he obtained, even if there is only one vehicle on the road he can see. The reason is radar has a typical range of approximately 400m (1200 feet), which is beyond the visual range of most human eyes. The radar might be clocking a speeder at a distance of 300m, but the policeman can only see an innocent driver coming towards him at a distance of 100m. As a result, an unjust ticket will be issued. Not to mention if there are more than two cars in his visual range, he will do some guesswork! From my conversations with a few anonymous policemen, I understand that some of them pick motorists at random, and make use of value judgement, implying there is an element of guesswork!!! One policeman agreed with me that there could be many unsuspecting innocent drivers who are unjustly booked. I also doubt if the radar saves the evidence in a retrievable format that can be presented to court should the guilt be challenged.

Furthermore, radar does not necessarily pick up the fastest moving object. The strongest return signal can be affected by a number of different factors, such as the target?s size, the cross-sectional area facing the radar antenna, its relative speed and the distance from the radar unit. For example, if a car is travelling at 80km/h 50 metres from the radar, and a truck is speeding at 110km/h at 200 metres away, the radar may pick up the return signal from the truck and register a speed of 110km/h. The police officer however might think that the car is the one responsible for the violation and therefore issues an undeserved ticket. In addition, when traffic radar is used near an international airport, the radar will pick up the return signals from airborne objects. In this case, extremely fast speeds such as 300-400km/h will be registered on the radar. Even if an aircraft is flying a few km away, the radar will still be capable to pick up the return signal since an aircraft is much greater in size and has much faster speed than any ground vehicle.

The authorities? objective is to enforce speed limit but the method used is not transparent enough since innocent motorists are sometimes targeted. This method has caused severe outcry in foreign democracies. Drivers should be vigilant, and when confronted with radar verdicts, should protest if they doubt the readings. We do not know the characteristics of the radar systems used by the police. It resides on the authorities to demonstrate, preferably in a televised report, how the system works, how readings are taken and how judgement is made. The public should be convinced that the system is foolproof. If there is any doubt, then it should be discarded.