A report of the operation and effectiveness of Random Breath Testing (RBT) in South Australia is prepared for each year. This report deals with RBT from 1989 to 1991. In April 1989, RBT operations were regionalised. Block testing continued to occur on a rotation basis involving the three metropolitan regions. A lower legal blood alcohol concentration (BAC) limit of .05 was introduced on 1 July 1991. The total number of drivers tested by year fell by 11% between 1988 and 1989, but increased by 9% between 1989 and 1990 and by 0.6% between 1990 and 1991, to be slightly lower than 1988 levels. There was a decrease in metropolitan testing of 17% between 1988 and 1989, with increases of 8% each year from 1990 to 1991. Increases in rural testing in 1989 and 1990 were not maintained, with a substantial decrease of 26% in 1991. From 1989 to 1991, an average of 31% of drivers were tested each year. The detection rate at RBT sites decreased in 1989 and 1990 to be, at 5.26 and 4.65 respectively, the lowest since 1981. Similar results were recorded in both metropolitan and rural areas. The 1991 detection rate was 5.72 overall, but this figure is not comparable with previous years since a new, lower legal BAC limit was introduced during 1991. A 1991 detection rate for drivers/riders with a BAC of .08 or above is estimated at 4.56, which continues the downward trend. However, no firm conclusions about the effectiveness of RBT can be made on the basis of detection rate data, due to variations in the method of RBT operation. (A)
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