LANSING, Mich. (AP) — A bill up for a vote in the Michigan Legislature could set the stage for setting a legal limit for driving under the influence of marijuana.

The House is expected to vote Tuesday to create a commission charged with researching and recommending a threshold of THC bodily content that would constitute evidence of impaired driving. THC is the component of marijuana responsible for most of the drug’s effects.

Unlike other Schedule 1 drugs, THC can be detected in the body long after it no longer affects someone’s driving ability.

Michigan’s law legalizing marijuana use for medical purposes shields patients from prosecution for drugged driving as long as they aren’t “under the influence” of marijuana. Legislators hope to define a limit similarly to how there’s a bodily alcohol content of 0.08.