Officer Tackleberry receives a call to a traffic accident. When he pulls up to the scene of the crash he sees a passenger car in the ditch and a man standing next to it. He observes that the man is holding himself up on the car trunk. The Officer approaches the man and asks him if he is okay and the man replies that he is fine, that he just ran off the road. The Officer notices the man is swaying, his breath wreaks of alcohol and his speech is badly slurred. Tackleberry has the man perform some sobriety tests and comes quickly to the conclusion that he is very drunk and decides to arrest him. However, the Officer does not tell the man he plans on arresting him and does not handcuff him yet. Instead Tackleberry asks the man questions about how much alcohol the man drank and other questions related to the crime of DWI. The Officer does not advise the man of his Miranda Rights. The man states he drank a lot of alcohol and probably should not have been driving and answers other question in a similar manner. The man is then arrested and processed.
At trial Tackleberry admits under oath that he planned on arresting the man prior to questioning him and the defense moves to block Tackleberry from testifying to the answers the man provided prior to arrest on the grounds that Tackleberry did not read him his Miranda Rights. The defense’s logic is that if the Officer already planned on arresting the man then he should have been given his rights prior to the questioning.

Was Miranda needed in this case since the Officer had already decided to arrest the man?
Remember the requirements for Miranda.
The person must be in custody (i.e. under arrest) and the Officer is questioning them about a crime. If those two things are not present then Miranda is not needed. The perceptions of a suspect don’t really mean much. Custody is judged by the standard of, would a reasonable innocent person believe they were not free to leave. Naturally a drunk driver who is doing SFST is probably thinking he is about to be arrested. Likewise the Officer can be planning to arrest someone and as long as they have not done it either literally or constructively they don’t have to do Miranda. Because of those issues the judge should rule that Miranda was not needed and the answers to the questions can be entered as evidence. Note I also said that the judge should rule that way, judges tend to do what they want.

Remember also there is no need to stop someone making spontaneous utterances and Mirandize them if they are saying incriminating things.