Nearly 15 per cent of the drivers who died in traffic accidents over the past five years had taken drugs, but only two drivers were charged with driving under the influence of drugs during the same period. Giving these figures yesterday, the government said there was no way at present of knowing exactly how many accidents and resulting casualties were caused by drivers under the influence of drugs other than alcohol. Secretary for Transport and Housing Eva Cheng said that while drug-driving was an offence, unlike alcohol there was no prescribed limit on the amount of medication for driving nor any rapid drug-screening device to help police ascertain if a driver had taken drugs. She was replying in the Legislative Council to a question from Liberal Party lawmaker Miriam Lau Kin-yee on why no mechanism was in place to support enforcement of the law. There were established parameters relating to drink-driving, and breath tests, 'but no relevant standards and arrangements are provided in the law on drug-driving offences', she said. 'Unlike alcohol, it is difficult to ascertain the effect of each type of drug on driving behaviour,' she said. 'There are various kinds of drugs ranging from over-the-counter medicine such as painkillers, cough mixture to prohibited dangerous drugs. The safe dosage for different drugs also differs.' According to autopsy reports provided by the government laboratory, traces of drugs were found in the blood of 35 of the 245 drivers who died in road accidents between 2004 and 2008, of whom 10 had also consumed alcohol. Although most of the drugs detected were pain killers and respiratory medication, 13 had taken drugs including ketamine, morphine and cocaine. But during that five years only two people had been prosecuted for drug-driving and both were convicted after admitting guilt. One was fined HK$1,000 and disqualified from driving for a year, while the other was prohibited from driving for six months and placed on probation for a year. Although police can now perform random breath tests on drivers, they can do little even if they suspect any of them are on drugs unless they breach alcohol laws. The bureau said police could ask drivers if they have taken drugs or search a vehicle if they had reasonable suspicion. If both moves fail to turn anything up, police could ask for blood or urine tests on drivers. A government source said Hong Kong could the follow the Australian model where hospitals were allowed to collect blood sample from drivers involved in accidents, not for prosecution but for statistical research so authorities could at least gauge the magnitude of the problem. Ms Cheng said the government would continue to look into the issue and study overseas jurisdictions but stressed that any amendments in legislation must be balanced with human rights and privacy considerations.