Blood test legislation in New Zealand

The 1969 compulsory blood test law, which also established an absolute blood alcohol limit for New Zealand drivers, is evaluated according to reported incidence of alcohol in road crashes and according to various surrogate measures involving road crashes. The 1974 amendment, which liberalised the criterion for “due cause to suspect”, is evaluated in terms of enforcement activity. It is concluded that the 1969 law did not have the kind of immediate effect that was achieved in Great Britain in 1967. There may have been a more gradual effect, but one cannot be confident that such an effect occurred. The difference in impact was almost certainly due to attendant circumstances and the quite different types of publicity given the alcohol campaigns in the two countries. It was clearly not attributable to differences in the statute's content or in its enforcement, which has always been relatively active and has increased over the years. The increase in enforcement activity seems to have been accelerated by the 1974 amendment.