Driving under the influence of marijuana is a crime in New York. This article explains the penalties imposed for DWI (driving while intoxicated) violations, but other laws regarding marijuana possession and sale could also apply to drivers and passengers.
It is illegal to drive a vehicle while under the influence of marijuana, alcohol, other drugs, or a combination of substances. When alcohol is involved, a blood alcohol level of .08% or more establishes the driver was "per se" intoxicated. However, for a driver to be convicted of a marijuana-related offense, the prosecution must show the driver was in an "intoxicated condition" (called a "DWI") or his or her ability to operate a vehicle was impaired (called a "DWAI") as the result of marijuana use.
Penalties vary according to whether the offense is a first or subsequent conviction. And, while not described here, harsher penalties may apply if certain aggravating circumstances—like an excessive BAC or minor passengers—are involved.
If you have been charged with a marijuana-related driving offense, consult an experienced criminal defense attorney. While the penalties and consequences of a marijuana charge are governed by statutory law, only a local criminal defense attorney can tell you how cases like yours tend to be handled by prosecutors and judges in your courthouse.