Can Anyone actually find a link to the AAA Study itself? This site links to FreeThoughtProject, which is hardly credible. The only link in the article at FTP just brings me to an ABC News election page. I tried googling, and I found another article abnout it, which offered this as a source: https://www.aaafoundation.org/impaired-driving-and-cannabis

Which seems to suggest quite the opposite...

"Fatal crashes involving drivers who recently used marijuana doubled in Washington after the state legalized the drug. Washington was one of the first two states to legalize the recreational use of marijuana, and these findings serve as an eye-opening case study for what other states may experience with road safety after legalizing the drug." (Yes, correlation doesn't equal causation, but still evidence in the opposite direction)

Other than that, all it says is...

"Legal limits, also known as per se limits, for marijuana and driving are arbitrary and unsupported by science."

Which makes sense, since people have significantly different tolerance levels.