A state commission says Michigan should not set a legal limit for how much of marijuana’s active ingredient motorists can have in their system.

The Impaired Driving Safety Commission spent nearly two years studying the effects of marijuana on people behind the wheel. Now they’ve forwarded their findings to Gov. Gretchen Whitmer and Michigan’s legislature.

The panel also recommended that Michigan continue to use roadside sobriety tests to determine if a driver is impaired instead, saying the levels of THC is person’s blood are not a “reliable indicator” of whether or not they are impaired.