Cabby questions use of GPS data in conviction
SINGAPORE — A taxi driver who knocked down and killed a pedestrian challenged the use of GPS data in proving he was speeding prior to the accident.
SINGAPORE — A taxi driver who knocked down and killed a pedestrian challenged the use of GPS data in proving he was speeding prior to the accident.
Appealing against his conviction and sentence of six months’ jail and an eight-year driving ban, Tan Hie Koon said yesterday he would have travelled beyond the point of the accident if he had been travelling at 78kmh that night, as estimated by the prosecution’s expert witness.
The 51-year-old’s lawyer Peter Ong argued, instead, that the accident could have been caused by a sudden failure of a mechanical component in his client’s eight-year-old vehicle, which had issues with its undercarriage that could affect steering control. He argued that his client could also have lost control of the car due to rapid air loss from a tyre where a nail was found embedded, as testified by the prosecution’s expert witness,a senior automotive engineer at STA Inspection.
Mr Ong also questioned the district judge’s decision to consider an eyewitness’ estimation of the speed his client was travelling at, describing itas “subjective”.
Tan had run over Ms Bui Thi Hon Mai, 31, along Geylang Road in the early hours of Sept 17, 2010. A motorist who witnessed the accident estimated Tan to be driving at between 70kmh and 80kmh, and added that traffic conditions were good and lighting was adequate. The prosecution’s expert witness put Tan’s speed at 78kmh.
In response, Deputy Public Prosecutor Chee Min Ping said Tan’s taxi had been sent for regular monthly maintenance, and the undercarriage problem had been rectified in August 2010, when the front brake padswere replaced.
She added that another witness, a senior consultant forensic scientist, had pointed out that the nail in the tyre could not have caused a puncture, and no tearing, bursting or enlargement of the tyre was found.
Ms Chee said scientific literature had been submitted to show that GPS data was generally accurate and reliable. She also said the GPS coordinates coincided with Tan’s account of where he was heading that day.
Nevertheless, Mr Ong said the sentence imposed on his client is “manifestly excessive”. He added that Tan had a good driving record prior tothe accident.
Judicial Commissioner See Kee Oon, who heard the appeal, said the circumstances leading to the accident were unusual, although they were not unheard of. He said he would review the evidence, and adjourned the case.