Not many serve time ( here in NY anyway) you need 8oz for it to become a real crime. Anything less is a violation (same as a speeding ticket) unless it is (i)in clear public view or; (ii)Burning in a public place.
And even the (i) and (ii) situations are just an FAT (field appearance ticket) so you do not usually get arrested unless the officer feels it is necessary to insure you go in front of a judge (ex: if you have a lot of tickets you never answered or a lot of license suspensions from no-show at court).
* an interesting note: In your pocket or in a car (concealed) is not a public place. A small baggie in the glove box or in your coat pocket is not in public view or in a public place so a cop who charges you with it better have a good reason to go in your car or search your person. If fact even if it is in plain view on your car seat, an officer has to articulate why he was looking in your car. A car is treated the same as your house, and even a cop better have "reasonable suspicion" to go up to your house and start looking in your windows.
