The District Attorney's Office and law enforcement officers around the state have started charging passengers of vehicles with DWI for allegedly doing something to encourage the act of DWI. The theory of prosecution is not much different from the average accomplice liability case. For example, if you agree to drive the get-away car in a bank heist, you are equally guilty of robbing the bank as you did something in furtherance of the crime. The statute that allows for prosecution under this theory is called "Parties to a Crime."
I recently represented the first client I know of that faced trial for misdemeanor DWI under an accomplice liability theory. Though my client was acquitted, the District Attorney's Office has made it clear that they are actively going to pursue more prosecutions of non-drivers in DWI cases.
Here's the link to a story that ran on the news concerning the recent case I handled: