It appeared to the police that the appellant was affected by drugs of some sort. His speech was slow and slurred and the pupils of his eyes were small. Breath testing was negative for alcohol. From relevant available material including the finishing positions of the respective vehicles, police experts assessed the appellant's impact speed at approximately 116 k.p.h. When later interviewed by police, some six hours after the collision, the appellant still appeared to be drug affected. He told police that he had been "on" benzo-diazepines, prescribed to enable him to "get off" a methadone habit. A urine analysis revealed the presence of a high level of benzo-diazepines and a level of morphine so high as to overload the analysing machine. A blood sample taken at the Austin Hospital detected amphetamine at a "low level", methyl-amphetamine at a "very high level", diazepam at a "very high level", temazepam at "a medium level", and oxazepam, nitrazepam, morphine and codeine at "low levels". The evidence was, not surprisingly, that the levels of benzo-diazapines were consistent with the consumption of huge quantities of these drugs. All drugs present, it was said, would seriously impair the capacity to drive a motor vehicle. The test results were also consistent with recent introduction or consumption of heroin and amphetamine. It was not in issue before the sentencing judge that the appellant was a chronic drug addict of long standing. His drug addiction was primarily heroin-based but included other licit and illicit substances. Dr. Odell from the Victorian Institute of Forensic Medicine reported that benzo-diazepines are psycho-active drugs, but that their effect when mixed with a cocktail of other drugs is difficult to predict.