Massachusetts Senate Members plan to visit Colorado next week to learn more about their experience of recreational marijuana legalization.

“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 Senator Jason Lewis.

Other states including Washington, Alaska and Oregon have all legalized cannabis (for both medical and recreational use). Massachusetts is hoping to avoid the mistakes other states had made early on. Massachusetts has already approved laws decriminalizing possession of marijuana (in small amounts) and patients who need medical marijuana for medical conditions.

Despite that Republican Governor Charlie Baker says he is “unalterably opposed” to legalizing recreational marijuana, the data makes a case for approving both medical and recreational use. Colorado’s marijuana tax revenues nearly double last year’s figures. The state brought in nearly $73.5m in the first seven months of 2015.