Professor Kerr observes that the case is easily distinguished from the precedent the Indiana Supreme Court relies upon (Miles v. State), where the police found the drunken defendant parked by the side of the car with his windows rolled down. Here, by contrast, the defendant was only "by the side of the road" pursuant to the police's seizure of the car pursuant to a traffic stop. He notes the famous case of Martin v. State, an Alabama state case taught in law schools nationwide for the proposition that the police cannot take an intoxicated person into "the public", then arrest him for public intoxication (so much of the 1L curriculum is about shattering student's prior conceptions of fairness as irrelevant to the law; Martin is memorable if for no other reason than as a pleasant break from that routine).
But aside from the seemingly specious legal reasoning of the decision, it also seems rather disastrous from a policy perspective. The state has a substantial interest in keeping intoxicated drivers off the road. One of the main ways it seeks to accomplish this is by encouraging drunk individuals to become intoxicated passengers instead. The whole point of a designated driver program is for non-intoxicated persons to drive their intoxicated friends home, rather than letting them drive drunk themselves. This decision seems to fly in the face of that public policy and, to the extent that it discourages the practice of designated driving, makes the state of Indiana considerably less