Here is a great article analyzing arrests for marijuana possession and paraphernalia in Ada County: https://www.idahostatesman.com/news/local/crime/article239237443.html
According to the article, people are more than twice as likely to be arrested by Meridian PD for misdemeanor marijuana possession than any other law enforcement agency in Ada County. Between May and December of 2019, 65 people were booked into the Ada County Jail for misdemeanor marijuana possession and/or paraphernalia, and of those 65 people, 38 were arrested by the Meridian PD. And of those 38 arrests, 21 involved a driver or passenger of a vehicle. See the results below.
Possession of marijuana can be charged as a misdemeanor or a felony, depending on the quantity the person possesses. If a person possesses less than 3 ounces, they'll be charged with misdemeanor possession, and if they possess any more than that, they'll typically be charged with felony possession.
Now, the general rule is that an officer can arrest a person for a misdemeanor if they have a warrant for the arrest or they witness the crime occur. So with misdemeanor marijuana possession, an officer has the discretion to make the arrest if they witness the suspect possess the drug. However, some officers will simply confiscate the drug, cite you, and send you on your way. This makes sense with the current overcrowding of the Ada County Jail and the fact that marijuana possession is considered a mid-level misdemeanor.
What's interesting is that even with the jail overcrowding, Meridian officers are opting to arrest, especially when the individual is the driver or passenger of the motor vehicle. But what's not included in the article is how many of those drivers and passengers were actually suspected of being under the influence of the drug.
Should officers have this much discretion in deciding who to arrest? With the overcrowding of our jail, should arresting people for marijuana possession really be a priority? And does arresting an individual actually deter the illegal conduct any more than confiscating the drug and issuing a citation? Questions to consider. But for now, the moral of the story is don't possess marijuana in Meridian.