It is part of the tax money, Bradley said. There are two different taxes. One tax is at the grower level and the other is for retail sales. He said studies have not begun yet. The CHP is in the startup phase and is waiting to receive the funding that it has been allocated. Janelle Dunham, an information officer with CHP headquarters in Sacramento, said the agency should receive the money beginning in the fiscal year 2018-19 and funding will continue until 2022-23. Studies will be to establish and adopt protocols to determine whether a driver is operating a vehicle while impaired, including impairment by the use of marijuana or marijuana products, and to establish and adopt protocols setting forth best practices to assist law enforcement agencies, Dunham said. It is not known what amount of THC will be settled upon to determine the legal limit in California. States such as Colorado and Washington, both of which legalized recreational marijuana in 2012, stipulate drivers with more than 5 nanograms of THC in their blood can be charged with a DUI. According to the Colorado Department of Transportation, however, law enforcement officers attribute arrests made surrounding cannabis on observations made in the field. Officials with the Colorado State Patrol did not respond to requests Medical marijuana for comment. If California decides to adopt similar standards for THC impairment, a ratio for marijuana-to-nanogram in the blood may not be simple to determine.