Hawaii’s drugged driving law is located at Haw. Rev. Stat. Ann. § 291E-61(a)(2). It states that a person commits the offense of operating a vehicle under the influence of an intoxicant if the person operates or assumes actual physical control of a vehicle "while under the influence of any drug that impairs the person's ability to operate the vehicle in a careful and prudent manner."
In other words, in Hawaii it’s a crime to drive while impaired from drug use. No blood testing standard is established in Hawaii – that is, there is no fixed amount of drugs within the blood system that determines conviction. Whether a driver is impaired is determined on a case-by-case basis and at the discretion of the prosecutor.
Hawaii’s drugged driving law is directed at the prohibition of controlled substances as defined in Hawaii codes. These controlled substances mirror the controlled substances regulated by federal law (and found at the Drug Enforcement Administration website). It’s not an acceptable defense to a drugged driving charge to claim that the driver is legally entitled to use the controlled substance.
A driver arrested for drugged driving in Hawaii will be charged with driving under the influence and subject to DUI penalties. A conviction for drugged driving will be considered as a prior offense for purposes of calculating punishment regardless of whether a subsequent offense is due to alcohol or drugs. Read more about Hawaii’s DUI laws.
Yes, there is an implied consent rule for blood and urine testing. The refusal to take the test cannot be admitted into evidence against the driver in Hawaii.