The science is actually pretty concrete regarding the impairing effects of THC. Because cannabis is a schedule 1 drug, it can be very difficult for researchers to get their hands on real world doses of THC. Instead, they use very low doses that are not relevant to what is actually sold at dispensaries. For a really good review of all things cannabis impairment, I would recommend looking through the following report by the Cannabis Control Commission in Massachusetts. A little long, but a lot of good information. https://mass-cannabis-control.com/wp-content/uploads/2019/01...