You can find information about blood concentration levels for drug driving offences in the Land Transport Act 1998. The Act has a schedule that lists the high-risk levels for different drugs. These levels are measured in nanograms per millilitre (ng/ml) of blood. You can also find tolerance levels for drug-driving offences in the same schedule. Tolerance levels are the amounts of a drug that you can have in your blood without being considered impaired. These levels are also measured in ng/ml. The schedule lists many different drugs, including Alprazolam, Amphetamine, and THC (cannabis), along with their high-risk and tolerance levels, as empowered by sections like ss 2, 167AAA, and 167AAB.