A bill championed by Hawaii's Gov. David Ige aims to ensure that driving under the influence of marijuana remains illegal and would also broaden the scope of drugs that cause impairment, reports Honolulu Civil Beat.

Hawaii law now only prohibits driving under the influence of substances on schedules of drugs that include marijuana, heroin, fentanyl and meth, all of which are Schedule 1 drugs. However, there have been recent attempts at both the state and federal levels to remove marijuana from lists of regulated drugs, notes the report.

In addition to safeguarding against the use of marijuana behind the wheel, House Bill 2399 would also broaden the definition of drugged driving to include the use of muscle relaxants, the tea drink kava and any drug that causes impairment.

The state Senate approved a narrower version of the measure that exempts caffeine and nicotine; differences in the lists of drugs will have to be addressed in conference committee, reports Civil Beat.

The state's Department of Transportation and numerous county police departments support the bill. Opponents raise several concerns including unnecessary penalizing of people who legally and safely use medications as well as uncertain testing methods for drug impairment.