FILE - In this Oct. 29, 2013, file photo, a man smokes marijuana inside his apartment where he uses a hydroponics system to grow his weed in Mexico City. The Mexican government has awarded, on Friday, Dec. 11, 2015,  four people the first permits allowing growing and possession of marijuana for personal use. The government’s medical protection agency says the permits apply only to the four plaintiffs who won a November Supreme Court ruling. The permits don’t allow smoking marijuana in the presence of children, or anyone who hasn’t given their consent. (AP Photo/Eduardo Verdugo, File)

How high is too high to drive?

22News found out what police do to identify people driving under the influence in western Massachusetts.