The Senate Special Committee on Marijuana was created last year in response to a likely 2016 ballot question that — if approved by voters — would allow pot to be used recreationally in Massachusetts.
A draft itinerary for the four-day trip starting Monday includes meetings and discussions with Colorado state regulators, legislators and law enforcement officials.
“We have recognized all along that the best way to really learn about the impact of legalizing marijuana is to spend time on the ground in the state that has the most experience with it, and that is Colorado,” said Sen. Jason Lewis, a Winchester Democrat who chairs the committee of 10 senators, eight of whom plan to be on the trip.
The visit is being paid for by Milbank Memorial Fund, a nonprofit foundation that specializes in health policy, Lewis said Friday.
Three other states — Washington, Alaska and Oregon — have legalized recreational pot.
A group called The Campaign to Regulate Marijuana Like Alcohol collected more than enough signatures last year to advance the proposed ballot question, which would allow Massachusetts residents 21 or older to possess up to 1 ounce of marijuana. It would also create a 3.75 percent state excise tax on retail marijuana sales that would be assessed on top of the state’s 6.25 percent sales tax.
Massachusetts voters approved two earlier ballot questions that decriminalized possession of small amounts of marijuana and authorized patients with certain medical conditions to use the drug.
“We don’t want to repeat the mistakes and the challenges we had in implementing the medical marijuana question,” said Lewis, referring to regulatory delays that kept the first dispensaries from opening until last year.
Regulating recreational marijuana would be even more complex, he said, with issues that include public safety, licensing, taxes and compliance with federal law.
Republican Gov. Charlie Baker and state Attorney General Maura Healey, a Democrat, are among those lined up against the proposed ballot question, with Baker saying he is “unalterably opposed” to legalizing marijuana.