HKSAR v. POON CHI HUNG WILLIAM

HCMA 278/99

IN THE HIGH COURT OF THE

HONG KONG SPECIAL ADMINISTRATIVE REGION

COURT OF FIRST INSTANCE

MAGISTRACY APPEAL NO. 278 OF 1999

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J U D G M E N T

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This concerns a ticket against the appellant for speeding. Allegedly, the appellant was targeted by a laser gun. The laser gun used is a "Laser Speed Detection System Model LTI 20-20" manufactured by Laser Technology, Inc. of Colorado in the United States. The evidence at the trial against the appellant came essentially from PW2, the police officer who operated the laser gun, and PW3, a representative from the vendor of the laser gun.

2. The appellant appears in person both here and below. The grounds of appeal relied upon by appellant contain 26 paragraphs in 9 pages. There is a supporting appeal bundle of many pages. The points raised in the grounds of appeal may be grouped into the following categories: -

(1) Technology

The appellant challenged the reliability of the speed detection device. For instance, the appellant said that the algorithm adopted for the laser gun is liable to give wrong readings.

(2) Procedure

The appellant complained that the trial magistrate did not give him sufficient opportunity to challenge the reliability of the laser gun. For example, the trial magistrate refused to allow the appellant to examine the laser gun.

(3) Evidence

The appellant complained that he was not given the opportunity to challenge the status of PW3 as an expert witness and the court wrongly treated the evidence of PW3 as expert evidence.

(4) Credibility

The appellant complained that the trial magistrate should not have believed PW2 and PW3 because the two witnesses had been effectively discredited by cross-examination.

(5) Facts

The appellant complained that the trial magistrate made unjustified findings of fact notwithstanding evidence from PW2 and PW3 to different tenor.

3. For reasons that will become apparent, I did not and do not propose to go into each and every point raised in the grounds of appeal. I will deal with the following matters.

Reliability of the Laser Gun

4. The trial records reveal that the appellant questioned the prosecution witnesses at length and in great technical detail about the laser gun used. In the end, the trial magistrate felt satisfied with the explanations given by the prosecution witnesses and held that the laser gun did accurately detect speed.

5. The use of laser gun to detect speeding has been a subject of controversy in Hong Kong for some time. Quite a few people have expressed doubts over the wisdom of using such device. Many bemoan that use of laser gun is a retrograde means of law enforcement because it does not provide foul-proof record as evidence. The appellant appeared determined to ascertain down to the last technical detail whether the laser gun used against him is reliable. During the hearing before me, the appellant said that although he believed laser can be used to measure distance he wondered if it can be used to detect speed. This is a fundamental challenge to the theoretical basis or principle of operation of laser guns.

6. As I told the appellant in court, the history and development of the use of electromagnetic waves for detection of distance, direction and speed is well documented in reading material readily available to the general public. I referred to a book called THE INVENTION THAT CHANGED THE WORLD - How a Small Group of Radar Pioneers Won the Second World War and Launched a Technological Revolution written by Robert Buderi ("the Invention Book"). The Invention Book tells the story, with sufficient technical explanation, of how radar technology was developed for distance, direction and speed detection. Chapter 16 of the Invention Book is specifically on how Charles Townes invented maser and laser in efforts to enhance the technology for distance, direction and speed detection. Townes won the 1964 Nobel Prize for physics. There is further mention of laser gun for traffic law enforcement in Chapter 21 of the Invention Book. The Invention Book has a Chinese edition and is for sale in Hong Kong book stores. Thus, although judges and magistrates may not be able to master esoteric theories of physics, it is now common knowledge which judges and magistrates can take judicial notice of that laser technology can be applied to detect speeding. Of a matter the court can take judicial notice, there is no need for the prosecution to adduce proof.

7. Although theoretically laser technology can be harnessed to detect speeding, it does not necessarily follow that every device using laser technology is capable of detecting speed accurately. For the hardware design or the software algorithm of the equipment may be faulty or imperfect. The laser gun used in this case was subjected to such challenge. The appellant questioned the prosecution expert witness about the clock rate of the crystal used by the laser gun in question but could not get the answer. It was and is suggested by the appellant that the clock rate of the crystal used may not be suitable for accurate speed detection purpose. The appellant further questioned the prosecution expert witness about the mathematics for determining speed from data collected by the laser gun. He also questioned the data sampling technique of the laser gun. The operation and output of the laser gun attracted even more questions. Apparently, if the police officer could not hold the laser gun with a steady hand, or the laser beam could not be pointed to the target for a sufficient length of time, or the angle at which the laser beam is pointed towards the target is of a certain value, the laser gun reading may be inaccurate.

8. I must say many of the questions raised by the appellant are in the nature of a scientific inquiry which is quite different from a legal inquiry. In a case like the present one, for the purpose of legal inquiry, courts generally adopt what is commonly called the "black box" approach. Never mind what is inside the box, if it is capable of consistently producing the same reliable results, the black box is accepted as good for the purposes of the law. In order to determine whether the black box is capable of producing consistent and reliable results, the courts usually look for some objective reference standard. In this respect, the prosecution relied on five pieces of evidence: -

(1) A certificate signed by an "electronic engineer" under section 28(1) of the Evidence Ordinance, Cap. 8 stating that the laser gun is accurate and functions properly within the manufacturer's specifications.

(2) Copy of product information issued by the manufacturer.

(3) Copy of report that the Superior Court of New Jersey in the U.S. has approved use of the laser gun.

(4) Copy of notice of approval by the English High Court of the use of the laser gun.

(5) Oral testimony of PW3; PW3 has a bachelor's degree in electronics and holds a certificate issued by the manufacturer of the laser gun that he is qualified to test and maintain the laser gun and to train operators of the laser gun.

9. As the appellant pointed out, (1), (2) and (5) are self serving evidence. Of course the manufacturer would meet the standards and specifications it sets for its product. Likewise a vendor would support the product he sells. The question is whether the standards and specifications are reliable. PW3 was questioned about what recognized standards the laser gun conforms to. Apparently, there is no internationally recognized standard for verifying the performance of laser guns.

10. As to (3) and (4), the appellant drew an analogy with fingerprint evidence. It is now common knowledge that courts in the United States accept a lower standard of proof for matching fingerprints. It is only right that before Hong Kong courts accept any standard that has been adopted by a foreign court, the rationale and the tests used by such foreign court should be scrutinized. It is not safe to take for granted the decision of a foreign court.

11. In my view, unless the laser gun has been tested with satisfactory results in accordance with some internationally recognized standard for verifying the performance of laser guns, there should be proof of its reliability in terms of consistency and accuracy by way of a battery of tests set by an acceptable independent expert. A suitable expert from one of the engineering or science faculties in Hong Kong should be able to design an experimental procedure for checking the operation and results of the laser gun used in field conditions. Alternatively, if an experimental procedure is proposed by the manufacturer, the procedure ought to be verified by a said expert. Then the experiments are performed periodically by a person or persons authorized to issue a certificate under section 28(1) of the Evidence Ordinance, Cap. 8 for proof. Obviously, both the said expert and the person who issues a section 28(1) certification should be made available for cross-examination if required.

12. As it is, there were only tests according to the manufacturer's specifications. Justice must be seen to be done. The trial magistrate could not be satisfied beyond reasonable doubt that the laser gun accurately detected the speed of the appellant's vehicle.

Reliability of the Expert

13. The appellant attacked the status of PW3 treated by the trial magistrate as expert. First, he contended that the trial magistrate did not give him the opportunity to challenge the qualifications of PW3 before the latter was allowed to give evidence. The record shows that PW3 was called as an expert, gave evidence in full and then the trial magistrate ruled that PW3 was qualified to give evidence as expert. When PW3 gave evidence, the appellant did question PW3 in depth and extensively on very technical matters.

14. I accept Miss Ko for the Respondent's argument that in truth the appellant had been given ample opportunities to challenge the qualifications of PW3 as an expert. There is no hard and fast rule that an expert must be cross-examined on his qualifications as an expert before he may be allowed to give the actual expert evidence. In appropriate cases, the court may allow an "expert" to give expert evidence on de bene esse basis if that helps the court to determine whether the witness is an expert.

15. Secondly, the appellant contended that PW3 had very little and only elementary academic training on the subject of laser technology and, on being questioned about various in-depth technical matters, the expert appeared to have no convincing answer. In the circumstances, the trial magistrate should not have accepted PW3 as an expert.

16. I do not think I am in any better position than the trial magistrate to say whether the explanations given by PW3 regarding, for example, the least square equation, is satisfactory answer to the appellant's challenge. Nor am I wiser about whether a one percent product return rate is acceptable as opined by PW3. In these respects, it is a matter for the judgment of the trial court. Even though I might have come to a different conclusion, I should not interfere.

17. The third ground of attack is that PW3 is the vendor of the laser gun. It is therefore contrary to accepted sense of justice to allow PW3 to give expert evidence on a product he sells. Again, justice must be seen to be done. On this ground, I found that the appellant does have a legitimate complaint.

18. For the reasons given, the proper course is to quash the conviction and set aside the sentence. So I did. The appellant was more interested in a re-trial to enable him to properly challenge the reliability of the laser gun. According to him, even if this case ends before me, he has other pending cases in which he will raise the same issues. Accordingly, I ordered that the case be remitted to the magistracy to be tried by a permanent magistrate. Since there is going to be a trial de novo, it was unnecessary to consider the other grounds of appeal regarding the trial magistrate's conduct of the trial and I note here for the record that there was no finding by me on those grounds.