In 2016, Californians voted to legalize the sale of recreational marijuana. But three years later, the very basics of regulating legal weed remain uncertain, and the new markets for marijuana have become another confounding California mess. It’s unclear how much marijuana can be consumed before police can make an arrest for driving under the influence, or whether the state can guarantee that marijuana being sold is safe and effective. Vaping—popular yet controversial—confuses the issue further. How can local and state governments bring more clarity to the new world of legal marijuana? Why is the black market for marijuana surviving, and even thriving, during the transition to legalization? And what regulations will ensure that legal weed delivers on its promises of crime reduction and increased tax revenue? UCLA Cannabis Research Initiative clinical psychiatrist Tim Fong, executive director of the Los Angeles Department of Cannabis Regulation Cat Packer, and UCLA criminal justice and drug policy scholar Brad Rowe visited Zócalo to discuss the regulatory challenges of bringing a black market into the light. Moderated by Rolling Stone columnist Amanda Chicago Lewis, this Zócalo event took place at Cross Campus, in downtown Los Angeles.