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b. “incapable of having proper control of the motor vehicle

This is probably the most difficult part in relation to offences involving driving under the influence of drink or drugs: how do we determine whether a person is “incapable of having proper control of the motor vehicle”?  Of course, there can be objective evidence (usually supported by a medical report) such as an erratic manner of driving, the occurrence of an accident, the driver smelt of alcohol or was unable to walk in a straight line, etc.  But all these require evidence to prove and can be subject to heated argument from the defendant.

 

Sections 39A and 39K of the Road Traffic Ordinance (Cap.374 of the Laws of Hong Kong) attempted to overcome this unsatisfactory situation.

 

For cases involving driving under the influence of drink, section 39A makes it an offence for any person “who drives or attempts to drive a motor vehicle, or is in charge of a motor vehicle, on any road with the proportion of alcohol in his breath, blood or urine exceeding the prescribed limit”; and “prescribed limit” is defined under section 2 of the same Ordinance as:

 

  • 22 micrograms of alcohol in 100 millilitres of breath;
  • 50 milligrams of alcohol in 100 millilitres of blood; or
  • 67 milligrams of alcohol in 100 millilitres of urine.

Once there is proof of the alcohol level by way of breath, blood or urine, the prosecution could simply lay a charge under section 39A instead of section 39 in most drunken driving cases and does not have to worry about how to prove whether the driver is “incapable of having proper control of the motor vehicle”. 

 

For cases involving driving under the influence of specified illicit drugs (please refer to Schedule 1A for the definition of specified illicit drugs), section 39K makes it an offence for any person “who drives or attempts to drive a motor vehicle, or is in charge of, a motor vehicle on any road while any concentration of a specified illicit drug is present in the person’s blood or urine (whether or not any other drug is also so present)”.  Therefore, again the prosecution does not need to prove whether the driver is “incapable of having proper control of the motor vehicle”.

 

But what about non-specified illicit drugs?  Sections 39A and 39K deal only with alcohol and specified illicit drugs.  For cases related to driving under the influence of non-specified illicit drugs, the prosecution would still have to produce sufficient evidence to show that the driver is “incapable of having proper control of the motor vehicle”.

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