New Mexico courts have found that questioning on a DWI case before the arrest happens is not subject to Miranda. In a normal DWI case, an officer might pull somebody over for weaving, and then they have a conversation with that person, and they suspect that person has been drinking, and they have that person get out of the car and do standard field tests.
Even if they’re not arrested, but they are not free to go at that time, the courts have found that is similar to traffic questioning off the side of a road, and therefore they do not have to Mirandize you before doing that portion of the DWI investigation. Once you are handcuffed and put in the back of the police car, the Miranda does apply to you in DWI cases.